Isan language

Thai depiction of Phra Isuan who is revered as guardian of Isan or 'the northeastern direction'.

In official Thai contexts, the language is classified as a dialect of the Thai language. It is academically and officially referred to by one of the following terms: Phasa Thai Tawan Ok Chiang Neua (Thai: ภาษาไทยตะวันออกเฉียงเหนือ /pʰaː săː tʰaj tàʔ wan ʔɔ`ːk tɕʰǐaŋ nɯːa/), 'Northeastern Thai language' or Phasa Thai Thin Isan (Thai: ภาษาไทยถิ่นอีสาน /pʰaː săː tʰaj tʰìn ʔiː săːn/), 'Thai language of Isan region' or 'Thai dialect of Isan'. In more casual contexts, the language is known in Thai as either Phasa Thai Isan (/pʰaː săː tʰaj ʔiː săːn/), 'Isan Thai language' or 'Isan language of Thailand' or the shorter form Phasa Isan (/pʰaː săː ʔiː săːn/), 'Isan language'.

The term 'Isan' was adopted in the late nineteenth century when the Khorat Plateau and the Lao peoples on the right bank were integrated into Siam (Thailand), and the local princes were replaced with regional governors that were grouped into new administrative regions called monthon, with the appearance of Monthon Isan in 1900. This was later applied to the entire region and later, to remove references to the Lao people and culture, to the region, its people and its language. The term was resurrected from Isanapura, an old Khmer city whose empire once extended into Isan, as well as a Sanskrit term for 'northeast', i.e., of Bangkok, and the aspect of Phra Isuan (BGN/PCGN Phra Isouane) or Shiva as guardian of the northeast direction.[9]

To Lao speakers in Laos and most of the linguistic minorities of Isan, the language is simply known as Phasa Lao (Lao: ພາສາລາວ /pʰáː săː láːw/, but is distinguished from the language of Laos by usages such as Phasa Lao Isane (Lao: ພາສາລາວອີສານ /pʰá ː săː láːw ʔiː săːn/), 'Isan Lao language' or 'Lao language of Isan' or Phasa Thai Lao (Lao: ພາສາໄທລາວ /pʰáː săː tʰáj láːw/, 'Lao Thai language' or 'Lao language of Thailand'. Phasa Thai Isane and Phasa Tai Isane, (both Lao: ພາສາໄທອີສານ /pʰáː săː tʰáj ʔiː săːn/), mean 'Isan Thai language' or 'Isan language of Thailand' and 'Isan people's language', respectively. In other languages of the world, the language is known as 'Isan' or translations of 'Northeastern Thai'.[7][8]

Native Isan speakers refer to their language simply as Phasa Lao (Northeastern Thai: ภาษาลาว /pʰáː săː láːw/), 'Lao language', or Phasa Tai Lao (Northeastern Thai: ภาษาไทลาว /pʰáː săː tʰáj láːw/), 'Lao people's language' or the homophonous Phasa Thai Lao (Northeastern Thai: ภาษาไทยลาว, 'Lao Thai language' or 'Lao language of Thailand'. References to the speech as the 'Lao language' is restricted to when in Isan or in private groups of native speakers, given the historical use of the word 'Lao' in Thai by peoples from other regions of Thailand but particularly Central Thailand and Bangkok as a prejudicial slur. In mixed settings, the terms Phasa Isan (Northeastern Thai: ภาษาไทอีสาน /pʰáː săː ʔiː săːn/, Phasa Tai Isan (Northeastern Thai: ภาษาไทอีสาน /pʰáː săː tʰáj ʔiː săːn/, 'Isan people's language' and Phasa Thai Isan (Northeastern Thai: ภาษาไทยอีสาน /pʰáː săː tʰáj ʔiː săːn/), 'Isan Thai language' or 'Isan language of Thailand' are also gaining in use, and the younger generation have begun to adopt the term 'Isan' over the 'Lao' used traditionally by the older generations.[9] The language is also affectionately or poetically known as Phasa Ban Hao (Northeastern Thai: ภาษาบ้านเฮา /pʰáː săː bȃːn háu/), 'Our home language' or 'our village language'.

Isan speakers became politically separated from other Lao speakers after the Franco-Siamese War of 1893 would lead Siam to cede all of the territories east of the Mekong to France, which subsequently established the French Protectorate of Laos. In 1904, Sainyabuli and Champasak Provinces were ceded to France, leading to the current borders between Thailand and Laos. A 25 km demilitarised zone west of the river banks allowed for easy crossings, and Isan remained largely neglected for some time. Rebellions against Siamese and French incursions into the region included the Holy Man's Rebellion (1901-1904), led by self-proclaimed holy men. The Lao people also joined in the rebellion, but was crushed by Thai troops in Isan.[14] At first, Isan was administered by Lao local rulers subject to the Siamese Court under the monthon system of administration, but this was abolished in 1933, bringing Isan under the direct control of Bangkok.[15]

Nationalistic aims to promote central Thai culture and language were directed at regional minorities, such as the Lao of Isan.

Heavy-handed nationalist policies were adopted in 1933 with the end of the absolute monarchy in Thailand. Many were instituted during the premiership of Field Marshal Plaek Phibunsongkhram (1938-1944). Although Lao languages were banned from education in 1871, a new public education and new schools were built throughout Isan, and only Thai was to be used by government and media. References to Lao people were erased and propagation of Thai nationalism was instilled in the populace. The language was renamed "Northeastern Thai".

Discrimination against the Isan language and its speakers was commonplace, especially when large numbers of Isan people began arriving in Bangkok in the latter half of the 20th century, permanently or for seasonal work. Although this blatant discrimination is rarer these days, most of these nationalistic Thaification policies remain in effect.[16]

Resistance to Thai hegemony continued. During the course of World War II and afterwards, the Free Thai Movement bases in Isan made links with the Lao Issara movement. After the implementation of Thaification policies, many prominent Isan politicians were assassinated, and some Isan people moved to Laos. The Communist Party of Thailand led insurrections during the 1960s and 1980s, supported by the communist Pathet Lao and some factions of the Isan populace.[17] Integration continued, as highways and other infrastructure were built to link Isan with the rest of Thailand. Due to population pressures and unreliable monsoons of the region, Isan people began migrating to Bangkok for employment. Isan speakers began to shift to the Thai language, and the language itself is absorbing larger amounts of Thai vocabulary. Universities such as Mahasarakham and Khon Kaen are now offering classes on Isan language, culture, and literature. Attitudes towards regional cultures have relaxed and the language continues to be spoken, but Thai influences in grammar and vocabulary continue to increase.[18][19]

American linguist Joshua Fishman developed the Graded Intergenerational Disruption Scale (GIDS) to categorise the various stages of language death. The expanded GIDS (EGIDS) is still used to explain the status of a language on the continuum of language death.[22] The written language for Isan—both the secular Tai Noy script and the religious Tua Tham script—are currently at Stage IX which is described as a "language [that] serves as a reminder of heritage identity for an ethnic community, but no one has more than symbolic proficiency." Today, only a handful of monks in charge of the ancient temple libraries in Isan, some local professors, and a few experts are able to read and write the language.[18]^:3-4[22]

The spoken language is currently at Stage VIA, or "vigorous", on the EGIDS scale, which is defined by Ethnologue as a language that is used for "face-to-face communication by all generations and the situation is sustainable". According to data from 1983, 88 percent of Isan households were predominantly Isan speaking, with 11 percent using both Thai and Isan at home, and only one percent using exclusively Thai.[18] Although this sounds promising for the continued future of the Isan language, there are many signs indicating that the language could reach Stage VIB, or "threatened", which is defined as a "language used for face-to-face communication within all generations, but it is losing users". As a strong command of Thai is necessary for advancement in most government, academic, and professional realms, and in order to work in areas like Bangkok where Isan is not the local language. The negative perception of the language, even among native speakers, often causes speakers to limit use of the language unless they are in the company of other Isan speakers. Parents may view the Isan language as a detriment to the betterment of their children, who must be able to speak central Thai proficiently to advance in academia or other career paths besides agriculture. Although there are large numbers of Isan speakers, the language is at risk from Thai relexification.[18] There is also a generational gap, with older speakers using more normative Lao features, whereas the youth are using a very "Thaified" version of Isan or switching to Thai generally. Many academics and Isan speakers are worried that the language may decline unless it can be promoted beyond its status as a de facto regional language and its written script rejuvenated. [23]

The greatest influence on the Isan language comes from Thai. This is because Isan has been the target of official assimilation policies aimed to erase the culture and language and force nationalism based around the Thai monarchy and Central Thai culture. Thai spoken and written language is the only language of television, most radio stations, signage, government, courts, hospitals, literature, magazines, social media, movies, schools and mandatory for job placement and advancement, participating in wider society, education and social rise. Through Thai, Isan has also absorbed influences from Chinese, mainly the Teochew dialect, as well as English. Thai has also begun to displace the language of city life in the provincial capitals and major market towns in the region.

Language shift is definitely beginning to take hold. There does exist a considerable gap in language use between current university age students and their parents or grandparents, who continue to speak relatively traditional forms of the language. Many Isan people growing up in Bangkok often are unfamiliar with the language, and a larger number of children, especially in Isan's major cities, are growing up speaking only Thai, as parents in these areas often refuse to transmit the language. Those young people who do speak the language often heavily code-switch and rely on Thai vocabulary. It is uncertain if any of these students are able to revert to a 'proper' Isan, as the language still suffers the stigma of a rural, backward language of people who could serve as a fifth column of Lao efforts to dominate the region.[23]

Isan essentially exists in a diglossia, with the high language of Central Thai used in most higher spheres and the low language, Isan, used in the villages and with friends and relatives. Formal, academic and pop culture often demand knowledge of Thai as, as few Isan people can read old texts or modern Lao ones and Isan does not exist in these spheres. The language in its older form is best preserved in the poor, rural areas of Isan, many of which are far from market towns and barely accessible by roads despite improvements in integration. Many Isan academics that study the language lament the forced Thaification of their language. Wajuppa Tossa, a Thai professor who translated many of the traditional Isan stories directly from the palm-leaf manuscripts written in Tai Noy noted that she was unable to decipher the meaning of a handful of terms, some due to language change, but many due to the gradual replacement of Lao vocabulary and because, as she was educated in Thai, could not understand some of the formal and poetic belles-lettres, many of which are still current in Lao.[23]

Isan speakers have the choice of choosing a language that is either Thai or Lao or somewhere in between, with code-switching between languages a prominent feature of typical Isan speech. For example, if a man asks his younger brother, 'What is that man drinking?', he may receive one of several following responses that all mean, 'Older brother, the man over there drinks tea':, ranging from one diglossic extreme, i.e., using only Standard Thai to the other, using only Lao vocabulary which is often distinct from Thai.

• พี่ ผู้ชายนั่นดื่มน้ำชาครับ, phi phuchai nan deum namcha khrap /pʰîː pʰûː tɕʰaj nân dɯ`ːm nám tɕʰaː kʰráp/
  Standard Thai
• พี่ ผู้ชายนั่นดื่มน้ำชาเด้อครับ, *phi phuchai nan deum namcha doe khap /pʰīː pʰȕː tɕʰáj nȃn dɯ̄ːm nâm tɕʰáː dɯ̂ː kʰāp/.
  Standard Thai, but switching over to Isan tones and use of the polite particle เด้อ, doe and a 'Lao-ised' pronunciation of the Thai male polite particle ครับ, khrap.
• พี่ ผู้ชายนั่นกินน้ำซาเด้อครับ, *phi phuchai kin namsa doe khap /pʰīː pʰûː tɕʰaj nân kin nâm sáː dɯ̂ː kʰāp/
  Mainly Isan vocabulary, but with Thai pronunciation and tones for ผู้ชาย, phuchai, and intrusion of the Thai male polite particle after the Isan one.
• อ้าย ผู้บ่าวพู้นกินน้ำซาเด้อ, *ai phubao kin namsa doe /ȃːj pʰȕː bāːo pʰûːn kin nâm sáː dɯ̂ː/
  Only using shared Lao vocabulary and pronunciation (devoid of Thai influence).
  Cf. Lao ອ້າຍ ຜູ້ບ່າວພູ້ນກິນນ້ຳຊາແດ່/Archaic ອ້າຽຜູ້ບ່າວພູ້ນກິນນ້ຳຊາແດ່, ay phoubao kin namxa dé /ȃːj pʰȕː bāːo pʰûːn kin nâm sáː dɛ̄ː/)

Isan has always been Thailand's poorest, less educated and most rural region, with the vast majority of the local population engaged in traditional wet-rice cultivation and animal husbandry despite the region's infertile, salty soils and unpredictable rains making the area prone to either drought or severe floods. Agriculture employs over half the population, with another quarter of the population engaged in it part-time. Although it contains one-third of the total population of Thailand, the region only generates 10.9 per cent (2013) of the country's GDP. As a result, millions of Isan people leave during the dry season to find temporary work in menial jobs whilst others emigrate for longer terms but still maintain permanent residences in the region, and Isan people can typically found as taxi drivers, porters, factory workers, construction workers, restaurant workers, salon assistants, sex workers, janitors and other professions that require few skills or education[24]

When Thai people can understand words and phrases, the language sounds very polite, for Isan tends to use pronouns more frequently and uses vocabulary that often has cognates in Thai formal or literary language, especially frozen expressions, but otherwise, many words in spoken Lao and Isan are cognates of terms that are no longer very polite in spoken Thai. For example, Thai has two words for 'wife', mia (เมีย /mia/) and phanraya (ภรรยา /pʰan ráʔ jaː/). In Thai, mia is used by men but it is impolite in mixed company and Thai women generally object to the term being used (such as hearing a group of men refer to their own wives as 'broad' or 'woman'), as it is often used in many Thai expressions and insults that are negative towards women, and phanraya is the everyday, polite form used in general conversation. Lao mia (ເມັຽ) and Isan (เมีย), /mía/, unlike Thai, did not evolve to have a negative connotation and continues as the common word for 'wife' in vulgar, casual and formal circumstances whereas Lao phanragna (Archaic Laoພັນຣຍາ/modern Lao ພັນລະຍາ) and Isan (ภรรยา), /pʰán lāʔ ɲáː/ sounds as 'bookish' as referring to someone's wife as a 'consort'. As there is little advantage to speaking Isan and by virtue of its negative perception, even amongst speakers, the language shift goes unabated.[25]

The Lao folk music molam (หมอลำ, /mɔ̆ː lám/, cf. Lao: ໝໍລຳ/ຫມໍລຳ or lam lao (/lám láːo/, cf. Lao: ລຳລາວ) has gained in popularity in Thailand, with many Isan singing artists featured during off-peak hours on Thai national television. Crown Princess Sirindhorn was the patron of the 2003 "Thai Youth Mo Lam Competition" and Isan-language variants of the central Thai luk thung (ลูกทุ่ง, /lȗːk tʰúŋ/, cf. Lao: ລູກທົ່ງ, /lȗːk tʰoŋ/, louk thông) music are accepted in national youth competitions. Within Isan, many students participate in mo lam clubs where they learn the music.[18] Universities are also now offering classes about Isan language, culture, former alphabets, and literature. The Isan people are also exposed to a steady trickle of Laotian immigrants, seasonal immigrants, students as daily visitors, merchants, traders, and fishers.[20] Isan is also connected with Laos by three bridges, which link the cities of Nong Khai-Vientiane (also by rail), Mukdahan-Savannakhét, and Nakhon Phanom-Thakhek along the Thai-Lao border, respectively. The language will likely continue to have Thai relexification and gradual language shift as possible threats to its existence.[18]

Isan shares its original Lao consonant inventory, which compared to Thai, means it lacks /r/ and /tɕʰ/ and the common allophone of the latter, /ʃ/. However, it also includes the sounds /ɲ/ and /ʋ/, although /ʋ/ is sometimes /w/ depending on the speaker and region.

There are two relatively common consonant clusters:

• /kw/ (กว)
• /kʰw/ (ขว,คว)

There are also several other, less frequent clusters recorded, though apparently in the process of being lost:

• /kr/ (กร), /kl/ (กล)
• /kʰr/ (ขร,คร), /kʰl/ (ขล,คล)
• /pr/ (ปร), /pl/ (ปล)
• /pʰr/ (พร), /pʰl/ (ผล,พล)
• /tr/ (ตร)

All plosive sounds are unreleased. Hence, final /p/, /t/, and /k/ sounds are pronounced as [p̚], [t̚], and [k̚] respectively.

^* The glottal stop appears at the end when no final follows a short vowel.

The vowels of the Isan language are similar to those of Central Thai. They, from front to back and close to open, are given in the following table. The top entry in every cell is the symbol from the International Phonetic Alphabet, the second entry gives the spelling in the Thai alphabet, where a dash (–) indicates the position of the initial consonant after which the vowel is pronounced. A second dash indicates that a final consonant must follow.

The vowels each exist in long-short pairs: these are distinct phonemes forming unrelated words in Isan, but usually transliterated the same: เขา (khao) means "he/she", while ขาว (khao) means "white".

The long-short pairs are as follows:

The basic vowels can be combined into diphthongs. For purposes of determining tone, those marked with an asterisk are sometimes classified as long:

Additionally, there are three triphthongs. For purposes of determining tone, those marked with an asterisk are sometimes classified as long:

View of Vientiane across the Mekong from Si Chiang Mai District, Nong Khai Province. Due to proximity and daily trade, the Isan speech of Nong Khai is almost indistinguishable from the Lao as spoken in Vientiane, the basis of the Laotian standard of the language.

The Vientiane dialect is spoken in northern Isan, in areas long-settled by Tai peoples from the early days of Lan Xang, such as Nong Bua Lamphu—once the seat of the ouparat (BGN/PCGN oupalat) of Lan Xang and later the Kingdom of Vientiane, Udon Thani, Chaiyaphum, Nong Khai and much of Loei provinces.[26] The Tai Wiang (Northeastern Thai: ไทเวียง /tʰáj wíaŋ/, Lao: ໄທວຽງ), or 'Vientiane people' of these areas were boosted by Siamese deportations of people from the left bank during the destruction of Vientiane in 1827 after the failed uprising of its last king, Chao Anouvong (RTGS Chao Anuwong). The Tai Wiang are also found in Khon Kaen and the Yasothon, where many districts traditionally speak Vientiane-like varieties. There are also a very small number of villages of Vientiane Lao speakers located in other regions of the Northeast.

Standard Lao is based on the speech of the old families of Vientiane as heard on television and broadcasts of government news media on radio. The dialect also extends over all Vientiane Province which surrounds the capital, as well as portions of Xaisômboun and Bolikhamxai provinces.[26] Many of the Lao-speaking regions of these areas were previously part of the Vientiane Province until administrative reforms led to their creation. As the city of Nong Khai, and much of the province, lies south on the opposite bank from Vientiane and is connected by bridge and several ferry services, the Isan speech of its inhabitants is almost indistinguishable from the speech of the Laotian capital.

Northern Lao is not common is Isan, where it is found in western Loei and pockets of Udon Thani surrounded by Vientiane Lao speakers, but it is the predominate form of the Isan language spoken in the portions of Northern Thailand, such as the eastern portions of Uttaradit and Phitsanulok provinces that border Xaignabouli Province, Laos and Loei. In Laos, the dialect includes the traditional speech of the city of Louang Phrabang and the surrounding province and Xaignabouli, where Lao speakers predominate. In the other northern provinces of Oudômxai, Houaphan, Louang Namtha and Phôngsali, native Lao speakers are a small minority in the major market towns but Northern Lao, highly influenced by the local languages, is spoken as the lingua franca between ethnic groups.[26] The dialect was once an important prestige language of Laos, since the capital was the royal seat of Lan Xang for much of its history, and even under French rule and the capital long since moved to Vientiane, the Lao royal family continued to rule and deliver royal speeches in a refined form of the dialect until the brutal civil war that ousted it in 1975.

Northern Lao is quite distinct from the other Lao dialects, even though it is spoken just to the north of the Vientiane Lao dialect region. In vocabulary and intonation, it is quite similar to Tai Lanna language, due to geographic proximity, the brief dynastic union of Lanna and Lan Xang and the emigration of thousands of people from Lanna to Louang Phrabang after the former capitulated to Burmese invasions in 1551.[29] Because of this, Northern Lao is classified by Ethnologue as a Chiang Saen language like Tai Lanna.[1] The most striking difference between Northern Lao is the differentiation of two vowels 'ໄ◌' and 'ໃ◌', analogous to Thai 'ไ◌' and 'ใ◌' in cognates. In Standard Thai, Standard Lao and all other Lao dialects, these vowels are both /aj/, but Northern Lao distinguishes the latter, 'ໃ◌', as /aɯ/, although in Houaphan, the vowel is /əː/ as it is in Phuan. This distinction is preserved from Proto-Tai, where 'ໃ◌' and Thai 'ใ◌' correspond to Proto-Tai */aɰ/ and 'ໃ◌' and Thai 'ไ◌' correspond to Proto-Tai */aj/, respectively.[30]

There are also a few minor differences in vocabulary that distinguish the speech of people of northern Laos, much of which is retained in the small areas of Isan where it is also spoken, such as western Loei.[30]

• ew, 'to play' (Northeastern Thai: เอว /ʔeːw/, Lao: ເອວ BGN/PCGN éo)
  Vientiane Lao lin (Northeastern Thai: หลิ้น /lȉn/, Lao: ຫລິ້ນ, cf. Thai: เล่น /lên/ RTSG len)
• ling, 'monkey' (Northeastern Thai: ลิง /lîŋ/, Lao: ລິງ)
  Vientiane Lao ling (Northeastern Thai: ลีง /líːŋ/, Lao: ລີງ, cf. Thai: ลิง /liŋ/)
• khanom pang, 'bread', (Northeastern Thai: ขนมปัง /kʰa᷇ʔ nǒm pâŋ/, Lao: ຂມົນປັງ BGN/PCGN khanôm pang
  Vientiane Lao khao chi (Northeastern Thai: เข้าจี่ /kʰȁo cīː/, Lao: ເຂົ້າຈີ່, cf. Thai: ขนมปัง /kʰaʔ nǒm paŋ/)
• khu, 'package' (Northeastern Thai: คู่ /kʰu᷇ː/, Lao: ຄູ່ BGN/PCGN khou)
  Vientiane Lao ho (Northeastern Thai: ห่อ /hɔ̄ː/, Lao: ຫໍ່, cf. Thai: ห่อ /hɔ̀ː/)

The dialect is also unique for only having five tones, although some speakers in the mountainous areas may use more tones due to influences from their respective languages.[30] Due to the distinctive high pitch high-falling tone on words live syllables starting with low-class consonants is considered to sound 'softer' or 'lighter' to Lao speakers of other dialects.[31]

Northeastern Lao or Phuan (BGN/PCGN Phouan) and is a associated with a distinct tribal Tai people. In Thailand, they are generally found in numerous villages of Sakon Nakhon and Udon Thani, and smaller concentrations in Bueng Kan, Nong Khai and Loei, but there are over two dozen Phuan villages scattered across northern and central Thailand where the Phuan were brought to develop the land, forced to dig canals and construct roads or defend the Siamese capital but were kept apart and forced to maintain their traditional black clothing and were thus able to preserve their language and identity. In Laos, the homeland of the Phuan people is the lowland areas of Xingkhouang and some districts of Houaphan.[26] As a northern-type language, the speech of Phuan communities is quite distinct from the neighbouring Isan villages where central and southern varieties predominate. Phuan preserves the distinction of 'ໃ◌' and Thai 'ใ◌', which correspond to Proto-Tai */aɰ/ and 'ໃ◌' and Thai 'ไ◌', which correspond to Proto-Tai */aj/, respectively. The former is realized as /əː/ and the latter as /aj/, similar to the Houaphan accent of the Northern Lao dialect.[30] Due to a tonal distribution more akin to Northern Lao and influences of Tai languages spoken in northern Laos, Phuan is classified as Chiang Saen language in Ethnologue.[1]

Due to the settlement of Phuan peoples outside of their original homeland of what is now Xiangkhouang Province of Laos, the tones of Phuan vary markedly between settlements due to drift because of isolation and influence of contact languages. However, there are a few traits that are shared between most Phuan varieties. Almost all Phuan speech have a distinct tone for words of low-class consonants marked with the mai ek (BGN/PCGN mai ék) that also appears in low-class consonant syllables with long vowels. Most Lao dialects pronounce all words with the same tone, regardless of consonant class, when marked with mai ek. Most Phuan dialects have six tones like most other Lao dialects, although some varieties spoken in Central Thailand and Northern Laos only have five.[30]

The central Lao dialect groupings predominate in the Lao provinces of Savannakhét and Khammouane, and the Thai province of Mukdahan and other regions settled by speakers from these regions.

Southern Lao is the primary dialect of Champassak, most of the southern portions of Laos, portions of Thailand once under its control, such as Ubon Rachathani, and much of southern Isan, as well as small pockets in Steung Treng Province in Cambodia.

Western Lao does not occur in Laos, but can be found in Kalasin, Maha Sarakham, and Roi Et Provinces.

• Central Thai (Thai Klang), is the sole official and national language of Thailand, spoken by about 20 million (2006).
• Northern Thai (Phasa Nuea, Lanna, Kam Mueang, or Thai Yuan), spoken by about 6 million (1983) in the formerly independent kingdom of Lanna (Chiang Mai). Shares strong similarities with Lao to the point that in the past the Siamese Thais referred to it as Lao.
• Southern Thai (Thai Tai, Pak Tai, or Dambro), spoken by about 4.5 million (2006)
• Phu Thai, spoken by about half a million around Nakhon Phanom Province, and 300,000 more in Laos and Vietnam (2006).
• Phuan, spoken by 200,000 in central Thailand and Isan, and 100,000 more in northern Laos (2006).
• Shan (Thai Luang, Tai Long, Thai Yai), spoken by about 100,000 in north-west Thailand along the border with the Shan States of Burma, and by 3.2 million in Burma (2006).
• Lü (Lue, Yong, Dai), spoken by about 1,000,000 in northern Thailand, and 600,000 more in Sipsong Panna of China, Burma, and Laos (1981–2000).
• Nyaw language, spoken by 50,000 in Nakhon Phanom Province, Sakhon Nakhon Province, Udon Thani Province of Northeast Thailand (1990).
• Song, spoken by about 30,000 in central and northern Thailand (2000).

The consonants of the old Tai Noy alphabet. Letter shapes have been preserved, with few changes, in the modern Lao alphabet.

The original writing system was the Akson Tai Noi (Northeastern Thai: อักษรไทน้อย /ák sɔ̆ːn tʰáj nɔ̑ːj/, cf. Lao: ອັກສອນໄທນ້ອຽ BGN/PCGN Akson Tai Noy), 'Little Tai alphabet' or To Lao (Northeastern Thai: โตลาว /to: láːo/, cf. Lao: ໂຕລາວ), which in contemporary Isan and Lao would be Tua Lao (Northeastern Thai: ตัวลาว /tuːa láːo/ and Lao: ຕົວລາວ, respectively, or 'Lao letters.' In Laos, the script is referred to in academic settings as the Akson Lao Deum (Lao: ອັກສອນລາວເດີມ /ák sɔ̆ːn láːo d̀ɤːm/, cf. Northeastern Thai: อักษรลาวเดิม RTGS Akson Lao Doem) or 'Original Lao script.' The contemporary Lao script is a direct descendant and has preserved the basic letter shapes. The similarity between the modern Thai alphabet and the old and new Lao alphabets is because both scripts derived from a common ancestral Tai script of what is now northern Thailand which was an adaptation of the Khmer script, rounded by the influence of the Mon script, all of which are descendants of the Pallava script of southern India.[29]

'Sri Ubon Rattanaram Museum' written in English and Isan in the Tai Noi script. This would be rendered as Northeastern Thai: พิพิธภัณฑ์ศรีอุบลรัตนาราม in the Thai script, identical to how it is in the Thai language, and Lao: ພິພິດທະພັນສີອຸບົນຣັດຕະນາຣາມ in the contemporary Lao.

The Tai Noi script was the secular script used for personal letters, record keeping, signage, songs, poems, stories, recipes, medical texts and religious literature aimed at the laity. The earliest evidence of the script in what is now Thailand is an inscription at Prathat Si Bunrueang in Nong Bua Lamphu dated to 1510, and the last epigraphic evidence is dated to 1840 AD, although large numbers of texts were destroyed or did not survive the heat and humidity. The use of the script was banned in 1871 by royal decree, followed by reforms that imposed Thai as the administrative language of the region in 1898, but these edicts had little impact as education was done informally by village monks. The written language survived to some degree until the imposition of the radical Thaification policies of the 1930s, as the Central Thai culture was elevated as the national standard and all expressions of regional and minority culture were brutally suppressed.[37] Many documents were confiscated and burned, religious literature was replaced by royally sanctioned Thai versions and schools, where only the Thai spoken and written language was used, were built in the region. As a result, only a handful of people, such as academic experts, monks that maintain the temple libraries and some elderly people of advanced age are familiar with and can read material written in Tai Noi script. This has led to Isan being mainly a spoken language, and when it is written, if at all, it is written in the Thai script and spelling conventions that distance it from its Lao origins.[29]

Signage in Isan written in the Tai Noi script was installed throughout Khon Kaen University in 2013. Students were surveyed after the signs were put up, and most had a favorable reaction to the signage, as over 73 per cent had no knowledge of a previous writing system prior to the forced adoption of the Thai language and alphabet. Lack of a writing system has been cited as a reason for the lack of prestige speakers have for the language, disassociation from their history and culture and for the constant inroads and influence of the Thai language. Revival of the written language, however, is hampered by lack of support. Despite the easement of restrictions and prejudice against Isan people and their language, the Thaification policies that suppressed the written language remain the law of the land in Thailand today. Although contemporary Lao people from Laos can read Tai Noi material with only a little difficulty, Isan speakers are generally unfamiliar with the Lao script due to lack of exposure.[18][22]

Screenshot of a karaoke VCD from molam singer, Jintara Poonlarp. In the Lao script, the lyrics seen would appear as 'ໜີໄປບວດໃຫ້ມັນແລ້ວສາບໍ້'.

The ban on all but the Thai language and alphabet in the classroom and official, public spheres rendered Isan speakers unable to read material written in the Lao language from Laos and forced them into a primarily oral culture, with all writing done in Thai with the Thai script. Eventually, Isan people developed an ad hoc system of transcribing their spoken language, using Thai spelling for cognate words, even those with consonant clusters that do not exist in Isan or Lao, but the core vocabulary of traditional Lao vocabulary is spelled analogously to what is used in Laos. To represent the different tones, as Lao dialects generally have six tones to the five of Thai, some writers use the rare tone marks written over 'ก'—'ก๋' and 'ก๊'—to better transcribe them. A more universal practice is the substitution of the letter 'ฮ' /h/ where the expected spelling would be 'ร' /r/ as many words in Isan have /h/ where the cognate term in Thai is /r/. This is similar to the Lao letter 'ຮ.' For example, the Proto-Tai word *rɤːn became the formal Thai: เรือน /rɯan/ but the commonplace word Northeastern Thai: เฮือน and Lao: ເຮືອນ, both pronounced /hɨ́ːan/. Similarly, traditionally Isan lacks the sound /tɕʰ/ and cognate words with Thai have /s/ instead, so writers often substitute 'ซ' for the Thai 'ช'. For example, Proto-Thai **ɟaːŋ became Thai: ช้าง /tɕʰáːŋ/ and Northeastern Thai: ซ้าง and Lao: ຊ້າງ, both pronounced /sȃːŋ/. The substitution of the other Thai letters that represent /tɕʰ/ is unknown with 'ส', although the Lao equivalent 'ສ' is used in Laos, such as Thai: ฉบับ /tɕʰaʔ bàp/ vs. Lao: ສະບັບ /sáʔ báp/. Isan speakers in this case use Thai spelling and Lao pronunciation.[38]

The use of the Thai alphabet and Thai spelling of cognate words provides a few challenges for accurately transcribing the Isan language. For instance, Isan and Lao have preserved a phonemic distinction between /j/ and /ɲ/, which in Lao is rendered separately with the letters 'ຢ' and 'ຍ', respectively. This differentiates Lao: ຢາ /jaː/, 'medicine,' and the similarly sounding Lao: ຍ່າ /ɲā/, 'paternal grandmother', whereas Isan speakers use 'ย' in both Northeastern Thai: ยา and Northeastern Thai: ย่า, respectively. The use of the Thai script and spelling rules, in terms of visual processing, contributes to the low prestige of the language. Since written in Thai script, the language looks fairly intelligible to Thai speakers even if the spoken language is different enough to cause misunderstandings. Because of these great phonological differences in tone, substitution of phonemes and simplification of consonant clusters, it further serves to make Isan to appear to be an inferior, substandard version of Thai and not its own unique variety. Nevertheless, this system is common in personal letters, social media and electronic communications between Isan speakers and is used to transcribe the lyrics of songs in the language, particularly the traditional Lao folk music molam'.[37]

An example of the Tai Tham alphabet formerly used in Laos and Isan for religious literature.

The Tai Tham was historically known in the Lao-speaking world as tua tham (ตัวธรรม /tùa tʰám/, cf. Lao ຕົວທຳ/Archaic ຕົວທັມ, Toua Tham), 'dharma letters', due to their use primarily as the written language of Buddhist monks. The script was introduced into what is now Laos and Isan from Lan Na during the reign of King Setthathirath, who was crowned king of Lan Na and later became king of Lan Xang—although a prince of the latter—bringing both mandalas in personal union from 1546 until 1551. During this brief period, the large volumes of literature from the libraries in Chiengmai were either taken or copied and brought to the Lao people.[39]

Evidence of its use in what is now Isan include two stone inscriptions, such as the one housed at Wat Tham Suwannakuha in Nong Bua Lamphu, dated to 1564, and another from Wat Mahaphon in Maha Sarakham from the same period. The script was only used by the very religious or taught to the monks, as many sacred Pali sutras were preserved on palm-leaf manuscripts.[40] The script was generally not known to the laity, who would have instead used the Tai Noy script for most day-to-day things, although some, such as those who had joined the monastery for various lengths of time, as is the custom among males in various Therevada Buddhist Tai cultures. Despite its use as the religious language, often used to transcribe Pali texts, it was also used to write literature aimed at other monks and religious scholars, as well as notes and marginalia, in the Lao language.

Although Tua Tham is an abugida, spelling words according to the same general rules as Thai and Lao, the alphabet is unique in having a very different design, featuring round shapes, several ligatures, special vowels only used at the start of words, several consonants that have variant forms when at the end of a syllable and the habit of stacking letters, with the second letter in a sequence, where permissible, is written under the first. The Thai and Tai Noy/Lao scripts were derived from that of the Khmer, and are thus more sharply angled. Both the Mon and Khmer scripts share common descent from Brahmi via contacts with southern Indian traders, soldiers and religious leaders that used a Pallava script.[40]

As a result of its general suppression, Isan speakers use Thai-language and Thai-alphabet materials, although many monks in Isan offer advice or explanations in the Isan language, many of which are available for recordings, but transcriptions of these are now taken using the Thai alphabet and not Tai Noy or Tua Tham. Like Tai Noy, only a handful of experts and some older monks in charge of maintaining temple libraries are able to read the old texts. Although no longer in use in Isan, the alphabet is enjoying a resurgence in Northern Thailand, and is still used as the primary written script for the Tai Lü and Tai Khün languages spoken in the border areas where Thailand, Laos, Burma and southern China meet.[39]

Inscription in the Khom script (Ancient Khmer script). This Khmer script, distinct from the devised script for secret messages of Ong Kommandam during the Holy Man's Rebellion, was used to write Buddhist, Brahmanic and ritual texts.

The Khom script (อักษรขอม /kʰɔ̆ːm/, cf. Lao ອັກສອນຂອມ, Aksone Khom) was not generally used to write the ancient Lao language of Isan, but was often used to write Pali texts, or Brahmanic rituals often introduced via the Khmer culture. Khom is the ancient Tai word for the Khmer people, who once populated and ruled much of the area before Tai migration and the assimilation of the local people to Tai languages. The modern Khmer alphabet is its descendant. It was generally not used to write the Lao language per se, but was often found in temple inscriptions, used in texts that preserve Brahmanic mantras and ceremonies, local mantras adopted for use in Tai animistic religion and other things usually concerned with Buddhism, Brahmanism or black magic, such as yantras and sakyan tattoos.

Also known by the same name is an obscure script that was invented for conveying secret messages that could not be deciphered by the French or Siamese forces that had divided Laos by Ong Kommandam, who had taken over as leader after the death of Ong Kèo during the Holy Man's Rebellion. As Ong Kommandam and many of his closest followers were speakers of Bahnaric languages spoken in southern Laos, most of the known texts in the language were written in Alak—Ong Kommandam's native language—and the Bahnaric Loven languages of Juk, Su' and Jru', and some in Lao.[41]

Although the shapes of the letters have a superficial resemblance to several writing systems in the area, it was not related to any of them. It enjoys some usage as a language of black magic and secrecy today, but only a handful of people are familiar with it. Although the word Khom originally referred to the Khmer, it was later applied to related Austroasiatic peoples such as the Lao Theung, many of which had supported Ong Kammandam.[41]

Thai and Lao (including Isan varieties) are all mutually intelligible, neighboring, closely related Tai languages. They share the same grammar, similar phonological patterns and a large inventory of shared vocabulary. Thai and Lao share not only core Tai vocabulary but also a large inventory of Indic and Austroasiatic, mainly Khmer, loan words that are identical between them. Even though Thai and Lao have their own respective scripts, with Isan speakers using the Thai script, the two orthographies are related, with similar letter forms as spelling conventions. A Thai person would probably be able to understand most of written Isan (written in Thai with Thai etymologically Thai spelling), and may be able to understand the spoken language with a little exposure.

Although there are no barriers of mutual comprehension between a Lao speaker from Laos and an Isan speaker from Thailand, there are several linguistic and sociological factors that make the mutual intelligibility of Thai and Lao somewhat asymmetrical. First and foremost, most Lao speakers have knowledge of Thai. Most Lao speakers in Laos are able to receive Thai television and radio broadcasts and engage and participate in Thai websites and social media in Thai, but may not speak the language as well since Lao serves as the national and official state and public language of Laos. Isan speakers are almost universally bilingual, as Thai is the language of education, state, media and used in formal conversation. Isan speakers are able to read, write and understand spoken Thai, but their ability to speak Thai varies, with some from more remote regions unable to speak Thai very well, such as many children before schooling age and older speakers, but competence in Thai is based on factors such as age, distance from urban districts and education access.[42]

Thai speakers often have difficulty with some of the unique Lao features of Isan, such as very different tonal patterns, distinct vowel qualities and numerous common words with no Thai equivalent, as well as local names for many plants that are based on local coinages or older Mon-Khmer borrowings. A large number of Isan words and usages in Lao of Laos are cognates with old Thai usages no longer found in the modern language, or through drift, evolved to mean somewhat different things. Some Isan words are thus familiar to Thai students or enthusiasts of ancient literature or lakhon boran, soap opera-like serials that feature based on ancient Thai mythology or exploits of characters in previous periods, similar to the preservation of 'thou' and 'thee' in West Country English or modern students trying to parse the dialogue of Shakespeare's plays. The use of Thai etymological spelling of Isan words belies the phonological differences. Tones, which are phonemic in all Thai languages, are enough to make some words out of context to be perceived as something else. Same can be said for certain vowel transformations that took place in Lao after spelling came to be, that radically alter the pronunciation. Differences are enough that the film Yam Yasothon (แหยม ยโสธร Yaem Yasothon, Isan pronunciation /ɲɛ̑ːm ɲā sŏː tʰɔ́ːn/), 'Hello Yasothon'—better translated as 'Smile and Laugh Yasothon'—is shown in cinemas outside of Northeastern Thailand with Standard Thai subtitles. The movie, which features Isan actors and actresses, takes place in the Isan region, and surprisingly for a Thai movie with nationwide release, a predominately Isan dialogue.[43]

Many Isan (and Lao) terms are very similar to words that are profane, vulgar or insulting in the Thai language, features which are much deprecated. Isan uses อี่ (/ʔīː/, cf. Lao: ອີ່) and อ้าย (/ʔâːj/, cf. Lao: ອ້າຍ/archaic ອ້າຽ), to refer to young girls and slightly older boys, respectively. In Thai, the similarly sounding อี, i (/ʔiː/) and ไอ้, ai (/ʔâj) are often prefixed before a woman's or man's name, respectively, or alone or in phrases which are considered extremely vulgar and insulting. This taboo expressions such as อีตัว "i tua", "whore" (/ʔiː nɔːŋ/) and ไอ้บ้า, "ai ba", "son of a bitch" (/ʔâj baː/).

In Isan and Lao, these prefixes are used in innocent ways as it does not carry the same connotation, even though they share these insults with Thai. In Isan, it is quite common to refer to a young girl named 'Nok' as I Nok (อี่นก, cf. Lao ອີ່ນົກ I Nôk or to address one's mother and father as i mae (อี่แม่, cf. Lao ອີ່ແມ່ I Mae, /ʔīː mɛ̄ː/) and I Pho (อี่พ่อ, cf. Lao ອີ່ພໍ່ i pho, /ʔīː pʰɔ̄ː/), respectively. Of course, as Thai only uses there cognate prefixes in fairly negative words and expressions, the sound of Isan i mae would cause some embarrassment in certain situations. The low status of the language is contributing to the language shift currently taking place among younger Isan people, and some Isan children are unable to speak the language fluently, but the need for Thai will not diminish as it is mandatory for education and career advancement.[23]

Isan speakers share the phonology of the Lao language of Laos, so the differences between Thai and Isan are the same as the differences between Thai and Lao. Even in shared vocabulary, differences in vowel distributions, tone and consonant inventory can hinder comprehension even with cognate vocabulary. In typical words, Lao and Isan lack the /r/ and /tɕʰ/, instead substituting /l/ and /h/ for instances of Thai /r/ and /s/ for Thai /tɕʰ/. Lao and Isan, however, include the sounds /ʋ/ and /ɲ/ which are replaced with Thai /w/ and /j/, respectively, in cognate vocabulary.

In the development of the Lao language, the consonant clusters in the historical Tai languages were quickly lost. Although they sometimes appear in the oldest Lao texts, as they were not pronounced they quickly disappeared from writing. Clusters were re-introduced via loan words from Sanskrit, Khmer and other local Austroasiatic languages as well as in more recent times, via French and English. In these instances, the loan words are sometimes pronounced with clusters by very erudite speakers, but in general these are also simplified. For example, although Lao: ໂປຣກຣາມ /proːkraːm/, via French: programme /pʁɔgʁam/, and maitri (Lao: ໄມຕຣີ /máj triː/) from Sanskrit: मैत्री /maj triː/ are common, more often than not, they exist as ໂປກາມ /poːkaːm/ and ໄມຕີ /máj triː/, respectively.

The Thai language preserved the consonant clusters from older stages of the Tai languages and maintains them in writing and in careful pronunciation, although their pronunciation is relaxed in very informal speech. Due to the highly etymological spelling of Thai, consonant clusters from loan words such as Sanskrit and English are carefully preserved and pronounced. Isan, as a descendant of Lao, does not traditionally pronounce these clusters as they are absent from the spoken language, except in some high-brow words, but they are always written, as Isan uses the Thai alphabet and Thai spelling of cognate words. Although Isan speakers write maitri Thai: ไมตรี and prokraem Thai: โปรแกรม, via English 'programme' or 'program' (US), they use the pronunciations máj tiː/ and /poː kɛːm/.

In the modern Lao script, and the old Tai Noi script once used in what is now Isan, 'ຮ' /h/, itself a modification of the letter 'ຣ' /r/, was used to represent words that etymologically had /r/ but were now /h/. Native words that did not undergo transformation to /h/ instead became /l/ and were spelled with 'ລ'. However, /r/ was retained in some religious, technical and academic vocabulary, as well as loan words from Sanskrit, Khmer, French and English. In these instances, the pronunciation of 'ຣ' /r/ is /r/ amongst erudite speakers, particularly older people and those in the diaspora, and /l/ generally. Reforms after 1975 replaced most instances of 'ຣ' /r/ with 'ລ' /l/ in writing and speech. In Isan, the letter 'ฮ' /h/ is used analogously to Lao 'ຮ' /h/, although the Thai spelling of 'ร' is retained even when speakers pronounce it as /l/, possibly because even Central Thai speakers use /l/ in relaxed and informal environments. A notable exception is the word for 'to dance' or lam (Northeastern Thai: ลำ /lám/), which is cognate to Thai: รำ /ram/, but also appears with /l/ in Lao: ລຳ.

Although there are more words that are /l/ than /h/ that descend from Proto-Southwestern /r/, Lao speakers in Laos tend to use words with /h/ more frequently and consistently. In Isan, possibly due to the massive influence of Thai, /l/ is gaining usage at the expense of /h/. However, increased usage of /l/ or /h/ in speech is not a defining characteristic, with varieties on both sides of the Mekong having different distributions, although greater use of /h/ in Isan would definitely be a mark of a very conservative, rural dialect.

• ^1 Old spelling, still used by older Lao and those in the diaspora.
• ^2 Used in academic, very formal, technical or religious terms and recent loan words from European languages.
• ^3 Dialectal variant.

The Proto-Tai sounds */ɟ/ and */ʑ/ had likely merged in Southwestern Tai, and developed into /tɕʰ/ in Thai, but this was later merged into /s/ in Lao and traditional Isan pronunciation. As a result of this, Isan speakers writing the language in the Thai orthography will sometimes replace 'ช' /tɕʰ/ with 'ช' /s/ in cognate vocabulary, but unless they are code-switching into Thai or in very formal contexts that demand increased use of Thai-language phrases, Isan speakers traditionally replace all /tɕʰ/ with /s/ in speech. In Lao, the letter 'ຊ' /s/ is used in analogous positions where one would expect Thai 'ช' /tɕʰ/ or the rare letter 'ฌ' /tɕʰ/, the latter of which occurs only in rare loan words from Sanskrit and Pali. The Thai letter 'ฉ' /tɕʰ/ is also pronounced /s/ in Isan, but for sake of tone, corresponds better to 'ส' /s/ even though it is not written out this way. In Lao, the letter 'ສ' /s/ is used in analogous positions. The Thai letter 'ฉ' is generally only found in ancient words of Sanskrit or Khmer derivation and recent loan words from Teochew or Hokkien.

Although Proto-Southwestern Tai maintained the distinctions of Proto-Tai */ɲ/, */j/, */ʰɲ/ and */ˀj/ into /j/, all of these merged into /j/ in Standard Thai. In the Lao-Phuthai languages and languages such as Phuan and Tai Lanna, /ɲ/ is the usual outcome although all these languages retain a small subset of words with /j/, with the distinction being phonemic. In the Lao alphabet, the two realisations are represented orthographically as 'ຍ' /ɲ/ and 'ຢ' /j/, although 'ຽ' traditionally replaced both letters at the end of syllables and in the combination now written 'ຫຍ', but this is still found in old writings and material produced by overseas Laotians of the older generations.

The loss of the distinction between /ɲ/ and /j/ in Thai occurred shortly after the adoption of writing, as there are some vestiges in the spelling. For instance, Proto-Tai */ˀj/, is suggested in the spelling of some Thai words with the sequence 'อย'. In Lao cognates, this developed into /j/ and not /ɲ/. Similarly, the Thai letter 'ญ' usually appears in loan words from Sanskrit, Pali, Khmer or Mon where /ɲ/ occurred in the source language, but is now /j/. In the handful of native Thai terms that have this spelling correspond to Lao /ɲ/.

The Lao language preserved /ɲ/ at the expense of /j/, represented separately by the consonants 'ຍ' and 'ຢ', respectively. Despite the fact that most instances of */ˀj/ in Proto-Tai correspond to /j/ in Lao, half the cases of Proto-Tai */j/ and all instances of */ʰɲ/ and */ɲ/ all became /ɲ/. In the Lao language of Laos, even words from Sanskrit, Pali, Khmer or Mon with consonantal /j/ are replaced by /ɲ/, whereas in the Isan variety, this might be somewhat less common due to the influence or interference of mandatory Thai in formal vocabulary but remains phonemic in common words of the everyday spoken language. As the Lao language of Isan is written in Thai according to Thai spelling rules, the distinction cannot be made by the orthography. As a result, ya Lao: ຢາ /jaː/, 'medicine', and gna Lao: ຍາ /ɲáː/, an honorary prefix used for addressing people similar in age to one's grandparents, correspond to Northeastern Thai: ยา, suggestive of /jaː/ only.

• ^1 This is from a different root altogether as Proto-Tai */jaːn/ was replaced in Thai.
• ^2 Thai pronunciations in formal and academic settings in Isan.

Isan speakers, similar to Lao speakers in Laos, often pronounce consonantal 'ว' at the start of syllables as /ʋ/, a sound which does not exist in Thai, where the sound is /w/. In Laos, the Lao letter 'ວ' is often pronounced /ʋ/. This trait is considered provincial in Thailand as it deviates from the standard language, but in Laos, the pronunciation is common, but historically was the mark of erudition or nobility. There is no difference in spelling, as this variation is an allophone of /w/, but it is the more common pronunciation overall in Isan and Laos.

'sin' or 'transgression'

• Thai เวร wen /weːn/ and Isan เวร /ʋéːn/, 'E-W-R'
• Lao ເວນ vén /ʋéːn/ 'E-V-N'

'walled city'

• Thai เวียง wiang /wiaŋ/ and Isan เวียง /ʋíaŋ/, 'E-W-^I-Y-NG'
• Lao wíaŋ viang /ʋíaŋ/, 'V-Y-NG'

Lao and Isan innovated a diphthongisation of certain vowels that follow consonant clusters C/w/. This can only occur with clusters /kw/ and /kʰw/ and only effects vowels /aː/, /a/ and /am/. In Isan using Thai script, this corresponds to the clusters 'กว' /kw/, 'ขว' and 'คว' as /kʰw/ and vowels, with the null consonant 'อ', such s 'อา' /aː/, 'อั' /a/ and 'อำ' /am/, respectively. In the Lao script, this corresponds to the clusters 'ກວ', 'ຂວ' and 'ຄວ' and the vowels with the null consonant 'ອ', viz., 'ອາ', 'ອັ' and 'ອຳ', respectively.

In cognate vocabulary with Thai where the diphthongisation occurs, the Lao spelling corresponds to the Thai spelling and suggests a similar pronunciation. This indicates that it is more recent development in the Lao-Phuthai languages that occurred after the adoption of writing in the fourteenth century. It is also restricted. Khwaeng (Thai: แขวง /kʰwɛ̌ːŋ/), which in Thai usually refers to a subdistrict in urban areas is cognate to the khwèng (Lao: ແຂວງ /kʰwɛ̆ːŋ/) which is used for 'province' although it historically referred to provincial districts, does not undergo diphthongisation and the cluster remains intact.

In abugida scripts, the inherent vowel /a/ is often unwritten, especially in many words from Sanskrit, Pali or Austroasiatic languages. Thai uses a number of Pali and Sanskrit roots to form new words, but just because the inherent vowels are pronounced in one word does not mean it will appear in another word with the same root. Thus, the pronunciation of many words of Indic derivation must be learned on a case-by-case basis, and little guides from spelling. For example, Thai 'ธรรม-' (from Sanskrit dharma धर्म /d̪ʱarma-/)appears as /tʰam máʔ/ in ธรรมนิตย์ thammanit /tʰam máʔ nít/ 'TH-R-R-M-N-^I-T-[Y]', 'moral person' but as /tʰam/ in ธรรมเกษตร, thamkaset /tʰam kàʔ sèːt/ 'TH-R-R-M-E-K-S-T-R', 'land of justice'.

Lao tends to go the opposite direction, and with the required writing of all vowels in the most recent spelling reforms, this can be seen, with Lao ທຳມະນິດ thammanit /tʰám māʔ nīt/ 'TH-AM-M-A-N-^I-D' and ທຳມະກະເສດ thammakasèt /tʰám māʔ ká sȅːt/ 'TH-AM-M-A-K-A-E-S-D'. Isan, follows Lao pronunciation, although educated speakers may pronounce the words in the Thai fashion. The Thai distinction is not justified by etymology, as both words derive from Sanskrit dharmanitya (धर्मनित्य /d̪ʱarmanit̪ja/) and dharmakṣetra (धर्मक्षेत्र /d̪ʱarmakʂetra/), originally meaning 'pious man' but adopted into Thai and Lao to refer to the land of pious people.

Nevertheless, the Isan pronunciation is considered provincial and uneducated, akin to the mispronunciation of English 'athlete' /ˈæθ liːt/ as *'athelete' */ˈæθ ə liːt/ in non-standard usage or 'arthritis' as *'arthuritis' */ɑːˈθ ə raɪ tɪs/ and is thus stigmatised. This process also effects sentences with Tai vocabulary, with /aʔ/ inserted after hard consonant to soften the sound and flow of speech, i.e., จักน้อยเด้อ, chak noy doe /tɕʰák káʔ nɔ̑ːj dɯ̄ː/, 'I shall in a little,' is often pronounced in Isan as *จักกะน้อยเด้อ *chakka noy doe /tɕʰák káʔ nɔ̑ːj dɯ̄ː/.
Cf. Lao ຈັກນ້ອຍນ້ອຽແດ່ chak noy dè /tɕʰák káʔ nɔ̑ːj dɛ̄ː/ vs. the casually pronounced *ຈັກກະນ້ອຍນ້ອຽແດ່, *chakka noy dè /tɕʰák káʔ nɔ̑ːj dɛ̄ː/.

'psychology'

• Thai จิตวิทยา chitwittaya /tɕìt wít tʰáʔ yaː/ and Isan จิตวิทยา /tɕít táʔ ʋít tʰāʔ ɲáː/, 'CH-^I-T-W-^I-TH-Y-A'
• Thai pronounced as *จิต-วิททะยา
• Isan pronounced as *จิตตะวิททะยา
• Archaic Lao ຈິຕວິທຍາ 'CH-^I-T-V-^I-TH-Y-A' and modern Lao ຈິດຕະວິດທະຍາ chitavitagna/chittavitthagna 'CH-^I-D-T-A-V-^ID-TH-A-GN-A', /tɕít táʔ ʋít tʰāʔ ɲáː/
• Derives from Sanskrit cit (चित् /tɕ/it/), 'mind' or 'soul' and vidya (विद्या /ʋid̪jaː/), '-ology'.

'fish'

• Thai มัสยา matya /mát jaː/ and Isan มัสยา /māt sá ɲăː/, 'M-^A-S-Y-A'
• Thai pronounced as *มัส-ยา
• Isan pronounced as *มัสสะยา
• Archaic Lao ມັສຍາ 'M-^A-S-GN-A' an modern Lao ມັດສະຍາ matsagna, /māt sá ɲăː/
• Derives from Sanskrit matsya (मत्स्य /mat̪sja/)

'philosophy'

• Thai ปรัชญา pratya /pràt jaː/ and Isan ปรัชญา /pát sā ɲáː/, 'P-R-^A-CH-Y-A'
• Thai pronounced as *ปรัช-ญา
• Isan pronounced as *ปัชซะญา
• Archaic Lao ປຣັຊຍາ 'P-R-^A-X-GN-A' and modern Lao ປັດຊະຍາ 'P-^A-D-X-A-GN-A'
• Derives from Sanskrit prajna (प्रज्ञा /praɟñaː/)

'Mekong River'

• Thai แม่โขง Maekhong /mɛˆː kʰǒːŋ/ and Isan แม่โขง /mɛ̄ː kʰɔːŋ/, 'AE-M O-KH-NG'
• Isan pronounced as *แม่ของ
• Lao ແມ່ຂອງ Mèkhong /mɛ̄ː kʰɔːŋ/ 'AE-M KH-O-NG'

'Chaiburi' (Thai name of the Lao province of Xaignabouli)

• Thai ไชยบุรี Chaiburi /tɕʰaj bù riː/ and Isan ไซยบุรี /sáj ɲāʔ bú līː/, 'AI-CH-Y-B-_U-R-^I'
• Isan pronounced as *ไซยะบุรี
• Archaic Lao ໄຊຍບຸຣິ 'AI-X-GN-B-_U-R-^I' and modern Lao ໄຊຍະບູລີ Xaignabouri/Xaignabouli 'AI-X-GN-A-B-_U-L-^II' /sáj ɲāʔ bú līː/

'Hanuman'

• Thai หนุมาน Hanuman /hàʔ nú maːn/ 'H-N-_U-M-AN' and Isan /หุลมาน/หุนละมาน Hunlaman /hŭn lāʔ máːn/ 'H-_U-L-M-A-N'/'H-_U-N-L-A-M-A-N'
• Archaic Lao ຫຸລມານ 'H-_U-L-M-A-N' and modern Lao ຫຸນລະມານ 'H-_U-N-L-A-M-A-N', /hŭn lāʔ máːn/
• But also Isan หนุมาน Hanuman 'H-N-_U-M-A-N' and Lao ຫະນຸມານ Hanouman 'H-A-N-_U-M-A-N'

The Thai diphthong 'เ◌ือ' /ɯa/ is often pronounced as /ɨːa/ in Isan and is analogous to Lao ເxືອ, which begins with a lengthened close central unrounded vowel as opposed to the close back unrounded vowel of Thai. This vowel is written analogously in Lao. Depending on dialect or region, some speakers in Laos or Isan may also use /ɯa/.

'month'

• Thai เดือน deuan /dɯan/ and Isan เดือน /dɨːan/
• Lao ເດືອນ duan /dɨːan/

'tiger'

• Thai เสือ seua /sɯ̌a/ and Isan เสือ /sɨ̆ːa/
• Lao ເສືອ /sɨ̆ːa/

Even Thai words with clear cognates in Lao and Isan can differ remarkably by tone. Determining the tone of a word by spelling is complicated. Every consonant falls into a category of high, middle or low class. Then, one must determine whether the syllable has a long or a short syllable and whether it ends in a sonorant or plosive consonant and, if there are any, whatever tone marks may move the tone.[44] Thai กา ka, crow, has a middle tone in Thai, as it contains a mid-class consonant with a long vowel that does not end in a plosive. In Standard Lao, the same environments produce a low-rising tone /kàː/ but is typically /kâː/ or rising-mid-falling in Western Lao.

Despite the differences in pattern, the orthography used to write words is nearly the same in Thai and Lao, even using the same tone marks in most places, so it is knowing the spoken language and how it maps out to the rules of the written language that determine the tone. However, as the Tai languages are tonal languages, with tone being an important phonemic feature, spoken Lao or Isan words out of context, even if they are cognate, may sound closer to Thai words of different meaning. Thai คา kha /kʰaː/, 'to stick' is cognate to Isan คา and Lao ຄາ, which in Vientiane Lao is pronounced /kʰáː/, which may sound like Thai ค้า kha /kʰáː/, 'to trade' due to similarity in tone. The same word in some parts of Isan near Roi Et Province would confusingly sound to Thai ears like ขา kha /khǎː/ with a rising tone, where the local tone patterns would have many pronounce the word with a rising-high-falling heavier on the rising. Although a native Thai speaker would be able to pick up the meaning of the similar words of Isan through context, and after a period of time, would get used to the different tones (with most Lao and Isan speech varieties having an additional one or two tones to the five of Thai), it can cause many initial misunderstandings.

Despite the similarities, the Thai and Lao languages have very different speaking styles. Thai speakers tend to use many euphemisms, cute expressions, word play or abbreviations and situations that require 'nuanced' usage or implied meanings. For instance, in relaxed and casual speech, pronouns are normally dropped unless needed for emphasis or disambiguation. With Bangkok serving as Thailand's primary city and home to the majority of media corporations, government, academic, entertainment and infrastructure as well as roughly a quarter of the population in its metropolitan area, the influence of Bangkok's urban slang permeates spoken language of most native Thai speakers.[45]

Lao conversations are often more direct. Although spoken Isan has its own set of flowery language, word play and strategic vocabulary, they are not as commonly invoked in speech but rather feature heavily in the lyrics of local musical forms such as molam and poetry. Lao speakers also tend to use most pronouns, especially the ones for 'I' and 'you' even in relaxed speech. In Thai and Lao, the increased usage of pronouns occurs in formal and polite usage whereas both reduce their usage in relaxed, casual speech. Thus, compared to Thai, Isan conversations can seem more abrupt, serious, formal to the point of distant to Thai speakers. This perception is nevertheless offset by the large number of Isan words that sound like or are cognate to Thai words that are considered vulgar, and the greater use of native Tai vocabulary which may seem simple compared to the generally larger proportion of Indic vocabulary in Thai.[45]

Although the majority of Isan words are cognate with Thai, and Thai influences are even creeping into the vocabulary, many basic words used in everyday conversation are either lacking cognates in Thai, but share them with Lao. Some usages vary only by frequency or register. For instance, the Thai question word 'เท่าไหร่' is cognate with Isan 'เท่าใด' /tʰāo daj/ and Lao 'ເທົ່າໃດ' /tʰāo daj/, but Isan and Lao tend to use a related variant form 'ท่อใด' /tʰɔ̄ː dàj/ and 'ທໍ່ໃດ' /tʰɔ̄ː dàj/, respectively, more frequently, although the usage is interchangeable and preference probably more related to region and person.

In other areas, Isan preserves the older Tai vocabulary. For example, the old Thai word for a 'glass', such as a 'glass of beer' or 'glass of water' was 'จอก' chok /tɕ̀ɔːk/, but this usage is now obsolete as the word has been replaced by Thai 'แก้ว' kaew /kɛ̑ːw/. Conversely, Isan and Lao continue to use 'จอก' and 'ຈອກ' chok to mean 'glass' (of water) as /tɕ̀ɔ̏ːk/, but Isan 'แก้ว' /kɛ̑ːw/ and Lao 'ແກ້ວ' kéo /kɛ̑ːw/ retain the earlier meaning of Thai 'แก้ว' as 'gem', 'crystal' or 'glass' (material) still seen in the names of old temples, such as 'Wat Phra Kaew' or 'Temple of the Holy Gem'. Nonetheless, a lot of cognate vocabulary is pronounced differently in vowel quality and tone and sometimes consonant sounds to be unrecognisable or do not share a cognate at all. For example, Isan บ่ bo /bɔː/ and Lao ບໍ່ /bɔː/ bo are not related to Thai ไม่ /mâj/, mai

• 1 Thai เท่าไหร่ is cognate to Isan เท่าใด, thaodai and Lao ເທົ່າໃດ, thaodai, /tʰāo daj/.
• 2 Thai แก้ว also exists as Isan แก้ว, kaew, and Lao ແກ້ວ,kèo /kɛ̑ːw/, but has the meaning of "gem".
• 3 Thai ทำ also exists as Isan ทำ, tham and Lao ທຳ, tham, /tʰám/.
• 4 Lao ເຮືອນ and Isan เฮือน also exist as formal Thai เรือน, reuan /rɯːan/.
• 5 Thai บ้าน also exists as Isan บ้าน, ban, and Lao ບ້ານ, bane, /bȃːn/.
• 6 Thai จริง also exists as Isan จริง, ching, and Lao ຈິງ, ching, /tɕiŋ/.

These now-obsolete Lao letters were once used to spell words of Pali and Sanskrit derivation, but were removed, reducing the consonant inventory and the similarity of spelling between Thai and Lao.

Isan and Lao have drifted away from each other mostly in terms of the written language. The Isan people were forced to abandon their traditional Tai Noy script and have come to use the Thai written language, or Isan written in Thai, for communication. In Laos, Tai Noy was modified into the modern Lao script, but several spelling changes in the language during the transition from the Lao monarchy to the communist rule moved Thai spelling and Lao spelling of cognate words further apart. Isan, writes all words with Thai cognates as they exist in Thai, with clusters, special letters only found in obscure Sanskrit words and etymological principles that preserve silent letters and numerous exceptions to Thai pronunciation rules although a small handful of Isan words, with no known or very obscure Thai cognates, are spelled more or less the same as they are in Lao.

Lao spelling in Laos was standardised in the opposite direction. Whilst previously written in a mixture of etymological and phonetical spellings, depending on audience or author, the language underwent several reforms that moved the language towards a purely phonetical spelling. During the restoration of the king of Louang Phabang as King of Laos under the last years of French rule in Laos, the government standardised the spelling of the Lao language, with movement towards a phonetical spelling with preservation of a semi-etymological spelling for Pali, Sanskrit and French loan words and the addition of archaic letters for words of Pali and Sanskrit origin concerning Indic culture and Buddhism.

Spelling reforms under the communist rule of Laos in 1975 were more radical, with the complete abolition of semi-etymological spelling in favour of phonetical spelling, with the removal of silent letters, removal of special letters for Indic loan words, all vowels being written out implicitly and even the elimination or replacement of the letter 'ຣ' /r/ (but usually pronounced /l/) in official publications, although older people and many in the Lao diaspora continue to use some of the older spelling conventions. The examples demonstrate the differences between Lao and Isan, using Thai orthography, but also that between archaic and modern Lao, as well as the general pronunciation and spelling practices between Standard Thai and Standard Lao in general.[47]

Numerous loan words from other languages, particularly Sanskrit and Pali, have numerous silent letters, sometimes even syllables, that are not pronounced in either Thai, Isan or Lao. In most cases, one of the final consonants in a word, or elsewhere in more recent loans from European languages, will have a special mark written over it (Thai ' ໌ '/Lao ' ໌ ' known in Isan as karan (การันต์)and Lao as karan/kalan (ກາລັນ/archaic ກາຣັນຕ໌ /kaː lán/).

In reforms of the Lao language, these silent letters were removed from official spelling, moving the spelling of numerous loan words from etymological to phonetical. For instance the homophones pronounced /tɕan/ are all written in modern Lao as ຈັນ CH-^A-N, chan, but these were previously distinguished in writing as ຈັນທ໌ CH-^A-N-[TH] or ຈັນທຣ໌ CH-^A-N-[TH]-[R], 'moon'; ຈັນທ໌ CH-^A-N-[TH] or ຈັນທນ໌ CH-^A-N-[TH]-[N], 'sandalwood' and ຈັນ CH-^A-N, 'cruel.' In Isan, using Thai etymological spelling, the respective spellings are จันทร์ CH-^A-N-[TH]-[R], จันทน์ CH-^A-N-[TH]-[N] and จัน, CH-^A-N, with the latter being a shared Lao-Isan word with no Thai cognate.

'Vientiane'

• Thai เวียงจันทน์ /wiaŋ tɕan/, wiangchan and Isan เวียงจันทน์ /ʋíaŋ tɕàn/, E-W-^I-Y-NG-CH-^A-N-TH-[N]
• Archaic Lao ວຽງຈັນທນ໌/ວຽງຈັນທ໌ V-Y-NG-CH-^A-N-[TH]/V-Y-NG-CH-^A-[TH] and modern Lao ວຽງຈັນ V-Y-NG-CH-A-N, /ʋíaŋ tɕàn/
• Derives from Lao ວຽງ, viang or 'walled city' and Sanskrit chandna (चन्दन tʃand̪ na/), 'sandalwood'.

'gear'

• Thai เกียร์ /kia/, kia and Isan เกียร์ /kiːa/, E-K-^I-Y-[R]
• Archaic Lao ເກັຽຣ໌ E-K-^I-Y-[R] and modern Lao ເກັຽ E-K-^I-Y, /kiːa/
• Derives from English 'gear' /ɡɪə/ (UK) or /ɡɪər/ (US).

'animal'

• Thai สัตว์ /sàt/, sat and Isan สัตว์ /sát/, S-^A-T-[W]
• Archaic Lao ສັຕວ໌ S-^A-T-[W] and modern Lao ສັດ S-^A-D, /sát/
• Derives from Sanskrit सत्त्वं, sattvam (/sat̪ tʋam/), 'living being'.

The oldest texts in the Tai Noy corpus show that the earliest stages of the Lao language had consonant clusters in some native words as well as many loan words from Khmer, Mon, other Ausroasiatic languages, Sanskrit and Pali. Although most of these were maintained in Thai pronunciation, these clusters were quickly abandoned, indicating that the Tai dialects that became the Lao language lacked them or that they lost them through separate language development. Unlike the Thai script, Lao preserves a subscript version of /l/ and /r/ ' ຼ ' that was commonly used in the ancient Tai noy script when these clusters were pronounced and written.

Some consonant clusters were maintained in the Lao language for some vocabulary, mostly of Sanskrit and Pali derivation and used in royalty or religious settings, but the most recent spelling reforms in the Lao language removed most of them. The Thai language has preserved all of them, and when Isan is written in Thai, cognates of Thai words are spelled as if they are pronounced in Thai, with consonant clusters that are usually not pronounced in Isan except some religious and technical terms.

'garlic'

• Thai กระเทียม krathiam /kràʔ tʰíam/ and Isan กระเทียม /káʔ tʰíam/, K-R-A-E-TH-^I-Y-M
• Ancient Lao ກຼະທຽມ/ກຣະທຽມ K-_L/R-A-T-Y-M/K-R-A-T-Y-M and modern Lao ກະທຽມ K-A-T-Y-M, kathiam /káʔ tʰíam/

'country'

• Thai ประเทศ phrathet /pràʔ tɛ̂t/ and Isan ประเทศ /páʔ tʰɛ̂t/, P-R-A-E-TH-S
• Ancient Lao ປຼະເທສ/ປະເທສ P-_L/R-A-E-TH-S/P-R-A-E-TH-S and modern Lao ປະເທດ P-A-E-T-D, phathèt /páʔ tʰɛ̂t/
• Derives from Sanskrit pradeśa (प्रादेश /prād̪eɕā/), 'country' or 'nation'

'to be entertained'

• Thai เพลินจิต ploenchit /pʰlɤn tɕìt/ and Isan เพลินจิต /pʰɤ́n tɕít/, E-PH-L-^I-N-CH-^I-T
• Ancient Lao ເພີຼນຈິຕ/ເພລີນຈິຕ E-PH-_L/R-^I-N-CH-^I-T/E-PH-L-^I-N-CH-^I-T and modern Lao ເພີນຈິດ E-PH-^I-N-CH-^I-D, phuenchit /pʰɤ́n tɕít/

'to be finished'

• Thai เสร็จ set /sèt/ and Isan เสร็จ /sét/, E-S-R-CH
• Ancient Lao ເສັຼດ E-S-_L/R-D modern Lao ເສັດ E-S-D, /sét/
• Derives from Khmer srac (ស្រេច /sratɕ/)

'Buddha'

• Thai พระพุทธเจ้า, Phra Phuttha Chao /pʰráʔ pʰút táʔ tɕâu/ and Isan พระพุทธเจ้า /pʰūt tʰāʔ tɕâu/, PH-R-A-PH-_U--TH-TH-E-CH-A
• Archaic Lao ພຣະພຸດທະເຈົ້າ/(rare) ພຼະພຸດທະເຈົ້າ PH-R-A-PH-U-D-TH-A-E-CH-A/PH-_L/R-A-PH-_U-D-TH-A-E-CH-A and modern Lao ພຣະພຸດທະເຈົ້າ/ພະພຸດທະເຈົ້າ PH-R-A-PH-_U-D-TH-A-E-CH-A/PH-A-PH-_U-D-TH-A-E-CH-A, Phra Phouttha Chao /pʰūt tʰāʔ tɕâu/
• Derives from Lao ພຣະ, phra or 'holy/royal', Sanskrit/Pali Buddha (बुद्ध /bud̪d̪ʱa/) and Lao ເຈົ້າ, chao or 'prince/lord.'

As consonants may have one value at the start of a consonant and one at the end, occasionally the same letter will be used to end one syllable and begin the next. This remains common in many loan words from Sanskrit and Pali, and was once the case in Lao orthography, but now the different consonant sounds are written out explicitly and no longer implied from older and confusing rules of spelling. Thai, with its etymological spelling, preserves the implied pronunciation of these geminated consonant groupings.

'girl of noble birth'

• Thai กุลนารี kunlanari /kun láʔ naː riː/ and Isan กุลนารี /kun lāʔ náː lí/, K-_U-L-N-A-R-^I
• Archaic Lao ກຸລນາຣີ/ກຸນລະນາຣີ K-_U-L-N-A-R-^I/K-_U-N-L-A-N-A-R-^I and modern Lao ກຸນລະນາລີ K-_U-N-L-A-N-A-L-^I, kounlanari /kun lā náː líː/
• Derives from Sanskrit kulanārī (कुलनारी /kulanaːriː/)

'good fortune'

• Thai วาสนา watsana /wâːt sàʔ năː/ and Isan วาสนา /ʋȃːt sáʔ năː/, W-A-S-N-A
• Archaic Lao ວາສນາ/ວາດສນາ V-A-S-N-A/V-A-D-S-N-A and modern Lao ວາດສະໜາ V-A-D-S-A-HN-A, vatsana /ʋȃːt sáʔ năː/
• Derives from Sanskrit vasna (वस्न /ʋasna/

'wife' (formal)

• Thai ภรรยา phanraya /pʰan ráʔ jaː/ and Isan ภรรยา /pʰán lāʔ ɲáː/, PH-R-R-Y-A
• Archaic Lao ພັຣະຍາ ພັນຣະຍາ PH-^A-R-A-NY-A/PH-^A-N-R-A-NY-A and modern Lao ພັນລະຍາ, phanragna /pʰán lāʔ ɲáː/
• Derives from Sanskrit bharya (भार्या /bʱarja/)

Lao uses two vowel symbols inherited from Tai Noy, one of which ' ໍ ' or the nikkhahit (ນິກຄະຫິດ /nīk kʰāʔ hĭt/) is used to denote the vowel /ɔː/ in open syllables where that is the final sound in the syllable and the other ' ົ ' or mai kan (ໄມ້ກົງ /mȃj koŋ/) which is used to denote the vowel /o/, both of which are sometimes implied in Thai orthography. The latter symbol is also used with some vowels with various meanings. The viram (Archiac ວິຣາມ/ວິລາມ /ʋī láːm/) was formerly used as a variant of Lao letter 'ຍ' in a word as well as several other uses.

'person' or 'people'

• Thai คน khon /kʰon/ and Isan คน /kʰón/, KH-N
• Lao ຄົນ KH-^O-N, khôn /kʰón/

'litter' or 'palanquin'

• Thai วอ wo /w/ and Isan วอ /ʋɔː/, W-O
• Lao ວໍ V-^O, vo /ʋɔ́ː/

'emerald'

• Thai มรกต morakot /mɔː ráʔ kòt/ and Isan มรกต, M-R-K-T
• Archaic Lao ມໍຣະກົຕ M-^O-R-A-K-^O-T and modern Lao ມໍລະກົດ, morakôt /mɔ́ː lāʔ kót/
• Derives from Sanskrit mārakata (मारकत /maː ra ka t̪a/)

'small'

• Thai น้อย noi /nɔ́ːj/ and Isan น้อย /nɔ̑ːj/, N-O-Y
• Archaic Lao ນ້ຽ N-Y and modern Lao ໜ້ອຍ/ຫນ້ອຍ noy HN-O-Y/H-N-O-Y, /nɔ̑ːj/

'to write'

• Thai เขียน khian /kʰĭan/ and Isan เขียน /kʰǐan/, E-KH-^I-Y-N
• Lao ຂຽນ KH-Y--N, khian /kʰǐan/

'green'

• Thai เขียว khiao /kʰĭau/ and Isan เขียว /kʰĭau/, E-KH-^I-Y-W
• Lao ຂຽວ KH-Y-V, khio /kʰĭau/

Both Thai, Lao and Isan only permit the final cosonants /k/, /ŋ/, /t/, /n/, /p/, and /m/, with many letters beginning a syllable with one sound and ending a syllable or word with another. Spelling reforms in Laos restricted the final consonants to be spelled 'ກ', 'ງ', 'ດ', 'ນ', 'ບ' and 'ມ' which correspond to Thai letters 'ก', 'ง', 'ด', 'น', 'บ' and 'ม', respectively. As Thai has retained these final consonants according to etymology, this has further moved Lao spelling from Thai and Isan written in Thai in a large number of common words.

'to draw a picture'

• Thai วาดภาพ watphap /wâːt pʰâːp/ and Isan วาดภาพ /ʋȃːt tʰāʔ pʰȃːp/, W-A-D-PH-A-PH
• Archaic Lao ວາດພາພ V-A-D-PH-A-PH and modern Lao ວາດພາບ V-A-D-PH-A-B, vatphap //ʋȃːt pʰȃːp//

'happiness'

• Thai ความสุข khwam suk /kʰwaːm sùk/ and Isan ความสุข /kʰuːám súk/, KH-W-A-M-S-_U-KH
• Archaic Lao ຄວາມສຸຂ KH-V-A-M-S-_U-KH and modern Lao ຄວາມສຸກ KH-V-A-M-S-U-K, khoam souk /kʰuːám súk/
• Derives from Lao ຄວາມ and Sanskrit sukh (सुख /suːkʰ/)

'ancient times'

• Thai อดีตกาล aditkan /ʔáʔ dìːt kàːn/ and Isan อดีตกาล /ʔáʔ dȉːt tʰāʔ kaːn/, O-D-^I-T-K-A-L
• Archaic Lao ອະດີຕກາລ/ອະດີຕການ O-D-^I-T-K-A-L/O-D-^I-T-K-A-N and modern Lao ອະດີດການ O-D-^I-D-K-A-N, /ʔáʔ dȉːt kaːn/
• Derives from Sanskrit atitkala (अतीतकाल /at̪iːt̪kaːla/)

The archaic vowels 'xັຽ' and 'xັມ' were replaced with existing vowels 'ໄ' and 'ຳ' as these pairs both represented /aj/ and /am/, respectively. The Lao vowel 'ໄxຽ' was also replaced by 'ໄ'.

'to update'

• Thai ตามสมัย tam samai /taːm sàʔ măj/ and Isan ตามสมัย /taːm sáʔ mȁj/, T-A-M-S-M-^A-Y
• Archaic Lao ຕາມສມັຽ/ຕາມສໄມ T-A-M-S-M-^A-Y/T-A-M-AI-S-M and modern Lao ຕາມສະໃໝ/ຕາມສະໃຫມ T-A-M-S-A-AI-HM/T-A-M-S-A-AI-H-M, tam samay /taːm sáʔ mȁj/.

'dharma'

• Thai พระธรรม phra tham /pʰrá tʰam/ and Isan พระธรรม /pʰāʔ tʰám/, PH-R-A-TH-R-R-M
• Archaic Lao ພຣະທັມ/ພຼະທັມ PH-R-A-TH-^A-M/PH-_L/R-A-TH-^A-M and modern Lao ພຣະທຳ/ພະທຳ PH-R-A-TH-AM/PH-A-TH-AM, phra tham /pʰāʔ tʰám/
• Derives from Lao ພຣະ phra or 'holy' and Sanskrit dharma (धर्म /d̪ʱarma/) via Pali dhamma

'disciplined' or 'educated person'

• Thai เวไนย wenai /wɛ naj/ E-W-AI-N-Y and Isan เวไนย /ʋī náj/
• Archaic Lao ວິໄນຽ/ວິນັຽ V-^I-AI-N-Y/V-^I-N-^A-Y and modern Lao ວິໄນ, vinay /ʋī náj/

In the abugida systems, open syllables are assumed to have /a/ or /aʔ/ following them. Modern Lao spelling requires that all vowels are written out, altering the spelling of numerous words and furthering the language from Thai. As this can alter the tone of the words, sometimes tone marks or silent /h/ are used to either represent the actual pronunciation of the word or restore it to its original pronunciation.

'city'

• Thai นคร nakhon /náʔ kʰɔːn/ and Isan นคร, N-KH-R /nāʔ kʰɔ́ːn/
• Archaic Lao ນຄອນ/ນຄຣ N-KH-O-N/N-KH-R and modern Lao ນະຄອນ, nakhone /nāʔ kʰɔ́ːn/
• Derives from Sanskrit nagara (नगर /na ga ra/)

'street'

• Thai ถนน thanon /tʰaʔ nǒn/ and Isan ถนน /tʰáʔ nŏn/
• Archaic Lao ຖນົນ TH-N-^O-N and modern Lao ຖະໜົນ/ຖະຫນົນ TH-A-HN-^O-N/TH-A-H-N-^O-N, thanône /tʰáʔ nŏn/
• Derives from Khmer tʰnɑl (ថ្នល់ /tʰnɑl/)

'paradise'

• Thai สวรรค์ sawan /sàʔ wăn/ and Isan สวรรค์ /sá ʋăːn/, S-W-R-R-[KH]
• Archaic Lao ສວັນຄ໌/ສວັນ S-V-^A-N-[KH]/S-V-^A-N and modern Lao ສະຫວັນ S-A-H-V-^A-N, savane /sá ʋăːn/
• Derives from Sanskrit svarga (स्वर्ग /sʋarga/

'vowel'

• Thai สระ sara /sàʔ ráʔ/ and Isan สระ /sáʔ lāʔ/
• Archaic Lao ສຣະ/ສະຣະ S-R-A/S-A-R-A and modern Lao ສະລະ S-A-L-A, sara /sáʔ lāʔ/
• Derives from Sanskrit sara (सर /sara/)

Lao uses a silent letter 'ຫ' /h/ in front of consonants 'ງ' /ŋ/, 'ຍ' /ɲ/, 'ນ' /n/, 'ມ' /m/, 'ລ' /l/, 'ຣ' /r/ or /l/ and 'ວ' /ʋ/ to move these consonants into the high tone class, used to alter the tone of a word. This is analogous to the use of 'ห' /h/ before the equivalent 'ง' /ŋ/, 'ย' /j/ (but in Isan, sometimes represents /ɲ/ and also 'ญ', which is /j/ in Thai and represents /ŋ/ in Isan), 'น' /n/, 'ม' /m/, 'ล' /l/, 'ร' /r/ (generally /l/ when in a digraph in Isan) and 'ว' /w/ (generally /ʋ/ in Isan.

As a legacy of the Tai Noy script, Lao writers can use the special ligature 'ໜ' HN instead or, when typesetting or rendering unavailable, it can be optionally be written 'ຫນ' H-N as well as 'ໝ' HM and modern alternative 'ຫມ'. Both 'ຫລ' H-L and 'ຫຣ' H-R have the same ligature form 'ຫຼ' H_L/R. Previous versions of the script also had special ligatures 'ພຽ' PHY ('ພ' + 'ຍ' /pʰj/) and 'ຫຽ' HY ('ຫ' + 'ຍ' /hj/) with the latter replaced by 'ຫຍ' HY /j/ (high class tone). Former ligatures such as SN and ML have disappeared or were split into syllables as consonant clusters were generally lost or replaced. For example, Archaic Lao ສນອງ SN-O-NG and ມຼາບຼີ M_L-A-B_R-^I have become in the modern language ສະໜອງ S-A-N-O-NG sanong /sáʔ nɔ̌ːŋ/, 'message' (derived from Khmer snaang ស្នង /snɑːŋ/) and ມະລາບີ M-A-L-A-B-^I malabi /mā láː biː/, approximation of endonym of the Mlabri people. Thai preserves writing the consonants together, although in the modern Thai language these consonants are separated by a vowel according to the current pronunciation rules.

Both Tai Noy and the current Lao alphabet lack equivalents to the Thai vowel ligatures 'ฤ', 'ฤๅ', 'ฦ' 'ฦๅ' and are mainly used to represent the sounds /rɯ/ or /ri/, /rɯː/, /lɯ/ and /lɯː/, respectively, although the latter two symbols are obsolete in modern Thai. These symbols were used to represent loanwords from Sanskrit 'ऋ' /r̥/, 'ॠ' /r̥̄/, 'ऌ' /l̥/ and 'ॡ' /l̥̄/, respectively, but these are relatively rare sounds in Sanskrit.

'Louang Phrabang'

• Thai หลวงพระบาง Luang Phrabang /lŭaŋ pʰráʔ baːŋ/ and Isan หลวงพระบาง /lǔːaŋ pʰāʔ bàːŋ/, H-L-W-NG PH-R-A-B-A-NG
• Archaic Lao ຫຼວງພຣະບາງ H_L/R-V-NG PH-R-A-B-A-NG and modern Lao ຫຼວງພະບາງ/ຫລວງພະບາງ H_L/R-V-NG PH-A-B-A-NG/H-L-V-NG PH-A-B-A-NG, Louang Phrabang /lǔːaŋ pʰāʔ bàːŋ/

'mouse'

• Thai หนู nu /nŭː/ and Isan หนู /nǔː/, H-N-_U
• Lao ໜູ/ຫນູ HN-_U/H-N-_U

'fruit'

• Isan หมาก mak /mȁːk/ H-M-A-K (cognate of Thai มะ- ma-, prefix in certain fruit names)
• Lao ໝາກ/ຫມາກ HM-A-K/H-M-A-K, mak /mȁːk/

'season'

• Thai ฤดู ruedu /rɯ́ duː/ and Isan ฤดู /lāʔ dùː/, RUE-D-_U
• Archaic Lao ຣະດູ R-A-D-_U/L-A-D-_U and modern Lao ລະດູ L-A-D-_U,radou/ladou /lāʔ dùː/
• Derives from Sanskrit ṛtū ( /r̥tuː/

'hermit'

• Thai ฤาษี, ruesi /rɯː sĭː/ and Isan ฤาษี /lɯ̄ː sǐː/, RUE-S-^I
• Archaic Lao ຣືສີ R-^UE-S-^I and modern Lao ລຶສີ L-^UE-S-^I, rusi/lusi
• Derives from Sanskrit ṛṣi or 'rishi' (ऋषि /r̥̄ʂiː/)

'mysterious'

• Archaic Thai ฦกลับ LEU-K-L-A-B and modern Thai ลึกลับ, lueklap /lɯ́k láp/ and Isan ลึกลับ, L-^EU-K-L-A-B
• Lao ລຶກລັບ L-^EU-K-L-A-B, luklap /lɯ́̄k lāp/

'famous'

• Archaic Thai ฦๅชา LUE-CH-A and Modern Thai ลือชา L-^UE-O-CH-A leucha /lɯː tɕʰaː/ and Isan ลือซา, L-^UE-O-S-A /lɯ́ː sāː/
• Lao ລືຊ່າ luxa /lɯ́ː sāː/

Traditionally, no punctuation exists in either Thai or Lao, with spaces used to separate lists, sentences and clauses, but otherwise words are written with no spaces between them. A few symbols include the cancellation mark 'x໌' used to mark letters in loan words that are not pronounced, the repetition symbol 'ໆ' used to indicate words or phrases are to be repeated, an ellipsis-like symbol 'ຯ' used to shorten lengthy phrases, such as royal titles or to indicate that following portions have been removed and the equivalent to the et cetera symbol 'ຯລຯ'. These all have equivalents in the Thai script as 'x์', 'ๆ', 'ฯ' and 'ฯลฯ'.

Other Thai symbols, such as '๏', used for marking the beginning of texts, lines or stanzas, '๛' to mark the end of chapters, 'ฯะ' to mark the end of stanzas and '๚' to mark the end of sections. These symbols could be combined to provide meaning. A similar system was in use in Laos but was later abolished. The system is mostly archaic in Thai texts, but is still taught as many old texts feature these symbols.

Lao only uses two of the tone marks 'x່' and 'x້', although 'x໊' and 'x໋' may occasionally be used to record idiosyncratic or emotional speech, as aids to capture tones of different dialects or onomatopoeia. In Thai, the equivalent tone marks are 'x่', 'x้', x๊ and x๋, respectively. Although in Thai, the third and fourth tone markers are rare, they are frequently used to approximate the tones of hundreds of Chinese (mainly Teochew, Hokkien and Hainanese) loan words, dialectal expressions and onomatopoeia.

'soy sauce'

• Thai ซีอิ๊ว si io /siː íu/ and Isan ซีอิ๊ว /síː íu/
• Lao ສະອິວ sa io /sá íu/ S-A-O-^I-W
• Derives from Chinese (Teochew) si iu (豉油 /si˩ iu˥/)

'Chinese noodle soup'

• Thai ก๋วยเตี๋ยว kuay tiao /kŭaj-dtĭeow/ and Isan ก๋วยเตี๋ยว /kȗːaj tiaːw/
• Archaic Lao ກ໋ວຽຕຽວ kouay thio /kȗːaj tiaːw/, mostly replaced in modern Lao by ເຝີ feu /fɤ̏ː/
• Derives from Chinese (Teochew) guė diou (粿條 /kue˥˨ tio˥/

In modern writing, Thai and Lao have both adopted the question mark "?", exclamation point "!", comma ",", parentheses "()", hyphen "-", ellipsis "...", and period "." from their respective English and French sources. Since Isan adopted the Thai punctuation via English, the quotation marks """" are used instead of guillemets, "«»", and spaces are not inserted before terminal punctuation marks. Although Lao speakers in Laos will often use French-style punctuation, English-style punctuation is increasingly becoming more commonplace in Laos.

• English: She says, "I am not leaving for the market!"
• Isan: เขาบอกว่า, "ข้อยบ่กับไปตลาดดอกเด!"
• Lao : ເຂົາບອກວ່າ «ຂ້ອຍບໍ່ກັບໄປຕະຫລາດດອກເດ» !
• Thai: เขาบอกว่า, "ดิฉันไม่กลับไปตลาดค่ะ!"

Since the use of Central Thai is deemed polite and mandatory in official and formal settings, Isan speakers will often use the Thai ครับ, khrap (/kʰráp/), used by males, and ค่ะ, kha (/kʰaʔ/), used by females, sometimes in place of or after the ones shared with Lao. Isan speakers, however, do not use the very formal particle ข้าน้อย, khanoy (/kʰȁː nɔ̑ːj/, cf. Lao: ຂ້ານ້ອຍ/archaic ຂ້ານ້ຽ) at the end of sentences. Also, the use of เจ้า, chao (/tɕâo/, cf. Lao: ເຈົ້າ) and formal โดย, doy (/doːj/, cf. Lao: ໂດຍ/archaic ໂດຽ, dôy), to mark the affirmative or "yes" is no longer used in Isan, instead this is replaced with the general ending particles or the equivalent Thai expression.

A very few compounds in Lao are left-branching, but most of the time they are right-branching, as they are almost always in Thai and Isan.

• Isan หมูส้ม mu som (/mŭː sȍm/, but Lao ສົ້ມໝູ/ສົ້ມຫມູ som mou, "sour pork", (/sȍm mŭː/. Cf. Thai หมูแหนม, mu naem (/mŭː nɛˇːm/).
• Isan ไก่ปิ้ง kai ping (/kāj pȋːŋ/), but Lao ປີ້ງໄກ່, ping kai, "barbecued chicken", (/pȋːŋ kāj/). Cf. Thai ไก่ย่าง, kai yang (/kàj jâːŋ/).

Lao and Isan share most of their vocabulary, tone, and grammatical features, and the barriers of comprehension that would exist between a Thai speaker and a Lao speaker are absent between speakers of Isan and Lao. Technical, academic, and scientific language, and different sources for loan words have diverged the speech to an extent. Isan has borrowed most of its vocabulary from Thai, including numerous English and Chinese (Min Nan) loan words that are commonly used in Thai. Lao, on the other hand, has influences from French and Vietnamese that come from the establishment of the Protectorate of Laos and its inclusion in French Indochina. In ordinary and casual speech, only a few lexical items separate Isan and Lao, and many dialects do not end at the border.[48]

The main thing that differentiates Isan from Lao is the use of numerous Thai words. The process accelerated with greater integration of Isan into Thai political control in the early 20th century. Thai words make up the bulk of scientific, technical, governmental, political, academic, and slang vocabularies that have been adopted in Isan. Many words used in Isan have become obsolete, such as the use of ขัว, khua (/kʰŭa/) and น้ำก้อน, nam kon (/nȃm kɔ̑ːn/), which exist in Laos as ຂົວ and ນ້ຳກ້ອນ, but replaced by Thai forms สะพาน, saphan, and น้ำแข็ง, nam khaeng, respectively. Thai, Isan, and Lao share vocabulary, but sometimes this can vary in frequency. For instance, Lao speakers use ສະພານ, saphan, as a more formal word for "bridge". The very formal Thai word for "house", เรือน, reuan (/rɯan/) is cognate to the common Isan เฮือน, heuan, and Lao ເຮືອນ, huan (/hɯ´an/). Although many Lao speakers can understand and speak Thai due to exposure to Thai publications and media, the official status of the language in Laos, pressure to preserve the Lao language, and unique neologisms and other influences differentiate the language from Thai. A few neologisms in Laos are unique coinages.

The French gunboat Lutin helped bring Laos under French control.

The incorporation of Isan into Siam prevented the Lao language spoken there from the adoption of French loan words. From 1893 till 1954, the French language was the administrative language of the Protectorate of Laos. The language continues to remain a second language of international diplomacy, higher education, government, and the old elite. Laos has been affiliated with La Francophonie since 1972, with full-member status in 1992. As of 2010, 173,800 people, approximately 3% of the population, were counted as French speakers.[49] French-language content is occasionally found on Lao national radio and television, as well as in the weekly La Renovateur and alongside English in publications of Khaosane Pathét Lao News.[50] In Isan, most words of European origin have entered the language via Thai, especially from English, which helps to differentiate the speech on either side of the Mekong River.

• 1 Lao ພົດຈະນານຸກົມ/Archaic ພົຈນານຸກົມ, phôtchananoukôm (/pʰōt tɕáʔ náː nū kom/), exists as an alternate of Thai cognate พจนานุกรม.
• 2 Also exists as Lao ຄົນສົ່ງໜັງສື, khône sông nangsue (/kʰón sōŋ năŋ sɯˇː/.

The French brought Vietnamese to Laos to boost the population of the larger cities and Vietnamese administrators to help govern the region. Large numbers of Vietnamese troops were stationed in Laos during at various times in Laos' history. This has enriched Lao with more Vietnamese influences which are not present in Isan.

• 1 ก๋วยเตี๋ยว comes from Teochew 粿條, kué tiāu (/kwɛ˧˥tiau˥/)
• 2 Isan เยื้อน exists in Lao as ເຍື້ອນ, gnuane (/ɲɯˆaːn/)
• 2 Isan เฮ็ดงาน exists in Lao as ເຮັດງານ (/hēt ŋáːn/)
• 3 Thai ทำงาน exists in Isan as ทำงาน and in Lao as ທຳງານ, tham ngane (/tʰám ŋáːn/)

A small handful of lexical items are unique to Isan and not commonly found in standard Lao, but may exist in other Lao dialects. Some of these words exist alongside more typically Lao or Thai usages.

• 1 Lao ນ້ຳກ້ອນ formerly existed as Isan น้ำก้อน, nam kon (/nȃm kɔ̑ːn/), but usage now obsolete.
• 2 Thai and Isan น้ำแข็ง also exists as Lao ນ້ຳແຂງ, nam khèng (/nȃm kʰɛ̆ːŋ/).
• 3 Lao ຂົວ formerly existed as Isan ขัว, khua (/kʰŭa/), but usage now obsolete.
• 4 Thai and Isan สะพาน also exists as formal Lao ສະພານ, saphane (/sáʔ pʰáːn/).
• 5 Thai and Isan หน้าต่าง also exists as Lao ຫນ້າຕ່າງ/ໜ້າຕ່າງ, natang (/nȁː tāːŋ/).
• 6 Thai and Isan กระดาษ also exists as Lao ກະດາດ/Archaic ກະດາສ, kadat (/káʔ dȁːt/).
• 7 Thai and Isan หนังสือ also exists as Lao ໜັງສື/ຫນັງສື, nangsue (/năŋ sɯˇː/).
• 8 Lao ມັງກອນ also exists as Isan มังกร, mangkon (/máŋ kɔ̀ːn/), referring to the dragon but not the month named after it.
• 9 Thai and Isan มกราคม also exists as Lao ມົກກະລາຄົມ/Archaic ມົກກະຣາຄົມ, môkkarakhôm (/mōk káʔ láː kʰóm/).
• 10 Lao ແຂວງ also exists as Thai and Isan แขวง, khwaeng (/kʰwɛ̌ːŋ/), when referring to provinces of Laos.
• 11 Thai and Isan จังหวัด exist as Lao ຈັງຫວັດ, changvat (/tɕaŋ ʋát/), when referring to provinces of Thailand.
• 12 Thai and Isan variant of มอเตอร์ไซค์, รถจักรยานยนต์, rot chakkrayanyon (/rót tɕàk kràʔ jaːn yon/), similar to Lao ລົດຈັກ[ກະຍານ]/Archaic ຣົຖຈັກຍານ, lôt chak[kagnane] (/lōt tɕák [káʔ ɲáːn]/).
• 13 Isan บัก is a local variant of Isan หมาก and Lao ໝາກ/ຫມາກ, mak (/mȁːk/).
• 14 The มะ in Thai มะละกอ is cognate to Isan หมาก and Lao ໝາກ/ຫມາກ, mak (/mȁːk/).

Nouns are not marked for plurals, gender nor are they declined for cases, and do not require an indefinite nor definite article. Plurals are often indicated with the use of classifiers, words to mark the special classes that nouns belong to. For instance, หมา (mǎː, ma) "dog" has the classifier โต (to, toː) which, as its meaning "body" implies, includes all things with legs, such as people, animals, tables, and chairs. "Three dogs" would be rendered as หมา ๓ โต (ma sam to, mǎː sǎːm toː), literally "dog three classifier".

Verbs are easily made into nouns by adding the prefixes ความ (khwam/kʰwaːm) and การ (kan/kːan) before verbs that express abstract actions and verbs that express physical actions, respectively. Adjectives and adverbs, which can function as complete predicates, only use ความ.

• แข่งม้า (khaengma/kʰɛ̀ːŋ.máː) "to horserace" (v.) nominalises into การแข่งม้า (kan khaengma/kːan kʰɛ̀ːŋ.máː) "horseracing" (n.)
• เจ็บ (chep/tɕèp) "to hurt (others)" (v.) nominalises into ความเจ็บ (khwam chep/kʰwaːm tɕèp) "hurt (caused by others)" (n.)
• ดี (di, diː) "good" nominalises into ความดี (khwam di, kʰwaːm diː) "goodness" (n.)

Pronouns Pronouns are often dropped in informal contexts, and are often replaced with nicknames or kinship terms, depending on the relation of the speaker to the person to whom is being spoken. Pronouns can also change depending on the register of speech, with many of the more formal pronouns borrowed from formal Thai speech registers. The more formal the language, the more likely that pronouns will not be dropped and that formal pronouns would be used. Pronouns can be pluralised by adding พวก (phuak, pʰuak) in front of the pronoun, e.g., พวกข้อย (phuak khoy/pʰuak kʰɔːj) is the same as เฮา (hao) or พวกเฮา (phuak hao/pʰuak haw). Age and status is important in determining usage. Younger boys and girls names are often prefixed with บัก (bak, bak) and อี่ (i, iː) respectively. Older males and females use อ้าย (ai, aːj) and เอี้อย (euay, ɯːaj) respectively instead. People who are much older may be politely addressed as aunt, uncle, mother, father, or even grandmother or grandfather depending on their age. Isan age-based name prefixes are often identical to or similar to vulgar, disparaging age-based name prefixes in Central Thai and should be avoided outside of Lao speaking regions in Thailand.

There is no general distinction between adjectives and adverbs, and words of this category serve both functions and can even modify each other. Duplication is used to indicate greater intensity. Only one word can be duplicated per phrase. Adjectives always come after the noun they modify; adverbs may come before or after the verb depending on the word. There is usually no copula to link a noun to an adjective.

• เด็กหนุ่ม (dek num, dek num) A young child.
• เด็กหนุ่ม ๆ (dek num num, dek num num) A very young child.
• เด็กหนุ่มที่ไว้ (dek num thi vai, dek num tʰiː vaj) A child who becomes young quickly.
• เด็กหนุ่มที่ไว้ ๆ (dek num thi vai vai, dek num tʰiː vaj vaj) A child who becomes young quickly.

Comparatives take the form "A X กว่า B" (kwa, kwaː), A is more X than B. The superlative is expressed as "A X ที่สุด (thisut, tʰiːsut), A is most X.

• เด็กหนุ่มกว่าผู้แก่ (dek num kwa phukae, dek num kwaː pʰuːkɛː) The child is younger than an old person.
• เด็กหนุ่มที่สุด (dek num thisut, dek num tʰiːsut) The child is youngest.

Because adjectives or adverbs can be used as predicates, the particles that modify verbs are also used.

• เด็กซิหนุ่ม (dek si num, dek siː num) The child will be young.
• เด็กหนุ่มแล้ว (dek num laew, dek num lɛːw) The child was young.

Verbs are not declined for voice, number, or tense. To indicate tenses, particles can be used, but it is also very common just to use words that indicate the time frame, such as พรุ่งนี้ (phung ni, pʰuŋ niː) tomorrow or มื้อวานนี้ (meu wan ni, mɯː vaːn niː) yesterday.

Negation: Negation is indicated by placing บ่ (bo, bɔː) before the word being negated.

• อีน้องกินหมากเลน (i nong kin mak len, iːnɔːŋ kin maːk len) Younger sister eats tomatoes.
• อีน้องบ่กินหมากเลน (i nong bao bo kin mak len, iːnɔːŋ bɔː kin maːk len) Younger sister does not eat tomatoes.

Future tense: Future tense is indicated by placing the particles จะ (cha, tɕaʔ) or ซิ (si, siː) before the verb.

• อีน้องจะกินหมากเลน (i nong cha kin mak len, iːnɔːŋ tɕaʔ kin maːk len) Younger sister will eat tomatoes.
• อีน้องซิกินหมากเลน (i nong see kin mak len, iːnɔːŋ siː kin maːk len) Younger sister will eat tomatoes.

Past tense: Past tense is indicated by either placing ได้ (dai, daj) before the verb or แล้ว (laew, lɛːw) after the verb or even using both in tandem for emphasis. แล้ว is the more common one, and can be used to indicate completed actions or current actions of the immediate past. ได้ is often used with negative statements and never for present action.

• อีน้องได้กินหมากเลน (i nong dai kin mak len, iːnɔːŋ daj kin maːk len) Younger sister ate tomatoes.
• อีน้องกินหมากเลนแล้ว (i nong kin mak len laew, iːnɔːŋ kin maːk len lɛːw) Younger sister (just) ate tomatoes.
• อีน้องได้กินหมากเลนแล้ว (i nong dai kin mak len laew, iːnɔːŋ daj kin maːk len lɛːw) Younger sister (definitely) ate tomatoes.

Present progressive: To indicate an ongoing action, กำลัง (kamlang, kam.laŋ) can be used before the verb or อยู่ (yu, juː) after the verb. These can also be combined for emphasis. In Isan and Lao, พวม (phuam, pʰuam) is often used instead of กำลัง.

• อีน้องกำลังกินหมากเลน (i nong kamlang kin mak len, iːnɔːŋ kam.laŋ kin maːk len) Younger sister is eating tomatoes.
• อีน้องกินอยู่หมากเลน (i nong kin yu mak len, iːnɔːŋ kin juː maːk len) Younger sister is eating tomatoes.
• อีน้องพวมกินหมากเลน (i nong phuam kin mak len, iːnɔːŋ pʰuam kin maːk len) Younger sister is eating tomatoes.

The verb 'to be' can be expressed in many ways. In use as a copula, it is often dropped between nouns and adjectives. Compare English She is pretty and Isan สาวงาม (literally lady pretty). There are two copulas used in Isan, as in Lao, one for things relating to people, เป็น (pen, pen), and one for objects and animals, แม่น (maen, mɛːn).

• นกเป็นหมอ (Nok pen mo, Nok pe mɔː) Nok is a doctor.
• อันนี้แม่นสามล้อ (an née maen sam lo, an niː mɛːn saːm lɔː) This is a pedicab.

Unlike English, which indicates questions by a rising tone, or Spanish, which changes the order of the sentences to achieve the same result, Isan uses question tag words. The use of question words makes use of the question mark (?) redundant in Isan.

General yes/no questions end in บ่ (same as บ่, "no, not").

• สบายดีบ่ (sabai di bo, saʔbaj diː bɔː) Are you well?

Other question words

• จั่งใด (changdai, tɕaŋdaj) or หยัง (nyang, ɲaŋ) เฮ็ดจั่งใด (het changdai, het tɕaŋ.daj) What are you doing?
• ใผ (phai, pʰaj) ใผขายไขไก่ (phai khai khai kai, pʰaj kʰaːj kʰaj kaj) Who sells chicken eggs?
• ใส (sai, saj) Where? ห้องน้ำอยู่ใส (hong nam yu sai, hɔːŋnam juː saj) Where is the toilet?
• อันใด (andai, andaj) Which? เจ้าได้กินอันใด (chao kin andai, tɕaw gin an.daj) Which one did you eat?
• จัก (chak, tɕak) How many? อายุจักปี (ayu chak pi, aːju tɕak piː) How old are you?
• ท่อใด (thodai, tʰɔːdaj) How much? ควายตัวบทท่อใด (khwai ɗua bot thodai, kʰwaj bot tʰɔːdaj) How much is that buffalo over there?
• แม่นบ่ (maen bo, mɛːn bɔː) Right?, Is it? เต่าไวแม่นบ่ (Tao vai maen bo, ɗaw vai mɛːn bɔː) Turtles are fast, right?
• แล้วบ่ (laew bo, lɛːw bɔː) Yet?, Already? เขากลับบ้านแล้วบ่ (khao kap laew bo, kʰaw gap baːn lɛːw bɔː) Did he go home already?
• หรือบ่ (loe bo, lɤː bɔː) Or not? เจ้าหิวข้าวหรือบ่ (chao hio khao loe bo, tɕaw hiw kʰaw lɤː bɔː) Are you hungry or not?

Answers to questions usually just involve repetition of the verb and any nouns for clarification.

• Question: สบายดีบ่ (sabai di bo, saʔbaj diː bɔː) Are you well?
• Response: สบายดี (sabai di, saʔbaj diː) I am well or บ่สบาย (bo sabai, bɔː saʔbaj) I am not well.

Words asked with a negative can be confusing and should be avoided. The response, even though without the negation, will still be negated due to the nature of the question.

• Question: บ่สบายบ่ (bo sabai bo, bɔː saʔbaːj bɔː) Are you not well?
• Response: สบาย (sabai, saʔbaj) I am not well or บ่สบาย (bo sabai, bɔː saʔbaːj ) I am well.