Vowel length

Stress is often reinforced by allophonic vowel length, especially when it is lexical. For example, French long vowels are always in stressed syllables. Finnish, a language with two phonemic lengths, indicates the stress by adding allophonic length, which gives four distinctive lengths and five physical lengths: short and long stressed vowels, short and long unstressed vowels, and a half-long vowel, which is a short vowel found in a syllable immediately preceded by a stressed short vowel: i-so.

Among the languages with distinctive vowel length, there are some in which it may occur only in stressed syllables, such as in Alemannic German, Scottish Gaelic and Egyptian Arabic. In languages such as Czech, Finnish, some Irish dialects and Classical Latin, vowel length is distinctive also in unstressed syllables.

In some languages, vowel length is sometimes better analyzed as a sequence of two identical vowels. In Finnic languages, such as Finnish, the simplest example follows from consonant gradation: haka → haan. In some cases, it is caused by a following chroneme, which is etymologically a consonant: jää "ice" ← Proto-Uralic *jäŋe. In non-initial syllables, it is ambiguous if long vowels are vowel clusters; poems written in the Kalevala meter often syllabicate between the vowels, and an (etymologically original) intervocalic -h- is seen in that and some modern dialects (taivaan vs. taivahan "of the sky"). Morphological treatment of diphthongs is essentially similar to long vowels. Some old Finnish long vowels have developed into diphthongs, but successive layers of borrowing have introduced the same long vowels again so the diphthong and the long vowel now again contrast (nuotti "musical note" vs. nootti "diplomatic note").

In Japanese, most long vowels are the results of the phonetic change of diphthongs; au and ou became ō, iu became yū, eu became yō, and now ei is becoming ē. The change also occurred after the loss of intervocalic phoneme /h/. For example, modern Kyōto (Kyoto) has undergone a shift: /kjauto/ → /kjoːto/. Another example is shōnen (boy): /seuneɴ/ → /sjoːneɴ/ [ɕoːneɴ].

Many languages make a phonemic distinction between long and short vowels: Arabic, Italian, Sanskrit, Japanese, Biblical Hebrew, Scottish Gaelic, Finnish, Hungarian, etc.

Consider, for instance, the following examples of minimal pairs in Italian:

Long vowels may or may not be analyzed as separate phonemes. In Latin and Hungarian, long vowels are analyzed as separate phonemes from short vowels, which doubles the number of vowel phonemes.

Vowel length contrasts with more than two phonemic levels are rare, and several hypothesized cases of three-level vowel length can be analysed without postulating this typologically unusual configuration.[2] Estonian has three distinctive lengths, but the third is suprasegmental, as it has developed from the allophonic variation caused by now-deleted grammatical markers. For example, half-long 'aa' in saada comes from the agglutination *saata+ka "send+(imperative)", and the overlong 'aa' in saada comes from *saa+ta "get+(infinitive)". As for languages that have three lengths, independent of vowel quality or syllable structure, these include Dinka, Mixe, Yavapai and Wichita. An example from Mixe is [poʃ] "guava", [poˑʃ] "spider", [poːʃ] "knot". In Dinka the longest vowels are three moras long, and so are best analyzed as overlong /oːː/ etc.

Four-way distinctions have been claimed, but these are actually long-short distinctions on adjacent syllables. For example, in kiKamba, there is [ko.ko.na], [kóó.ma̋], [ko.óma̋], [nétónubáné.éetɛ̂] "hit", "dry", "bite", "we have chosen for everyone and are still choosing".

The vowels of Received Pronunciation are commonly divided into short and long phonemes. The short vowels are /ɪ/ (as in kit), /ʊ/ (as in foot), /ɛ/ (as in dress), /ʌ/ (as in strut), /æ/ (as in trap), /ɒ/ (as in lot), and /ə/ (as in the first syllable of ago and in the second of sofa). The long vowels are /iː/ (as in fleece), /uː/ (as in goose), /ɜː/ (as in nurse), /ɔː/ as in north and thought, and /ɑː/ (as in father and start). While a different degree of length is present, there are also differences in the quality (lax vs tense) of these vowels. In General American, only tenseness is usually distinguished and vowels are transcribed without the length mark.

Vowel length may often be traced to assimilation. In Australian English, the second element [ə] of a diphthong [eə] has assimilated to the preceding vowel, giving the pronunciation of bared as [beːd], creating a contrast with the short vowel in bed [bed].

Another common source is the vocalization of a consonant such as the voiced velar fricative [ɣ] or voiced palatal fricative, e.g. Finnish illative case, or even an approximant, as the English 'r'. A historically-important example is the laryngeal theory, which states that long vowels in the Indo-European languages were formed from short vowels, followed by any one of the several "laryngeal" sounds of Proto-Indo-European (conventionally written h₁, h₂ and h₃). When a laryngeal sound followed a vowel, it was later lost in most Indo-European languages, and the preceding vowel became long. However, Proto-Indo-European had long vowels of other origins as well, usually as the result of older sound changes, such as Szemerényi's law and Stang's law.

Vowel length may also have arisen as an allophonic quality of a single vowel phoneme, which may have then become split in two phonemes. For example, the Australian English phoneme /æː/ was created by the incomplete application of a rule extending /æ/ before certain voiced consonants, a phenomenon known as the bad–lad split. An alternative pathway to the phonemicization of allophonic vowel length is the shift of a vowel of a formerly-different quality to become the short counterpart of a vowel pair. That too is exemplified by Australian English, whose contrast between /a/ (as in duck) and /aː/ (as in dark) was brought about by a lowering of the earlier /ʌ/.

Estonian, a Finnic language, has a rare phenomenon in which allophonic length variation has become phonemic after the deletion of the suffixes causing the allophony. Estonian had already inherited two vowel lengths from Proto-Finnic, but a third one was then introduced. For example, the Finnic imperative marker *-k caused the preceding vowels to be articulated shorter. After the deletion of the marker, the allophonic length became phonemic, as shown in the example above.

In non-Latin writing systems, a variety of mechanisms have also evolved.

• In abjads derived from the Aramaic alphabet, notably Arabic and Hebrew, long vowels are written with consonant letters (mostly approximant consonant letters) in a process called mater lectionis e.g. in Modern Arabic the long vowel /aː/ is represented by the letter ا (Alif), the vowels /uː/ and /oː/ are represented by و (wāw), and the vowels /iː/ and /eː/ are represented by ي (yāʼ), while short vowels are typically omitted entirely. Most of these scripts also have optional diacritics that can be used to mark short vowels when needed.
• In South-Asian abugidas, such as Devanagari or the Thai alphabet, there are different vowel signs for short and long vowels.
• Ancient Greek also had distinct vowel signs, but only for some long vowels; the vowel letters η (eta) and ω (omega) originally represented long forms of the vowels represented by the letters ε (epsilon, literally "bare e") and ο (omicron – literally "small o", by contrast with omega or "large o"). The other vowel letters of Ancient Greek, α (alpha), ι (iota) and υ (upsilon), could represent either short or long vowel phones.
• In the Japanese hiragana syllabary, long vowels are usually indicated by adding a vowel character after. For vowels /aː/, /iː/, and /uː/, the corresponding independent vowel is added. Thus: あ (a), おかあさん, "okaasan", mother; い (i), にいがた "Niigata", city in northern Japan (usually 新潟, in kanji); う (u), りゅう "ryuu" (usu. 竜), dragon. The mid-vowels /eː/ and /oː/ may be written with え (e) (rare) (ねえさん (姉さん), neesan, "elder sister") and お (o) [おおきい (usu 大きい), ookii, big], or with い (i) (めいれい (命令), "meirei", command/order) and う (u) (おうさま (王様), ousama, "king") depending on etymological, morphological, and historic grounds.
  • Most long vowels in the katakana syllabary are written with a special bar symbol ー (vertical in vertical writing), called a chōon, as in メーカー mēkā "maker" instead of メカ meka "mecha". However, some long vowels are written with additional vowel characters, as with hiragana, with the distinction being orthographically significant.
• In the Korean Hangul alphabet, vowel length is not distinguished in normal writing. Some dictionaries use a double dot, ⟨:⟩, for example 무: "Daikon radish".
• In the Classic Maya script, also based on syllabic characters, long vowels in monosyllabic roots were generally written with word-final syllabic signs ending in the vowel -i rather than an echo-vowel. Hence, chaach "basket", with a long vowel, was written as cha-chi (compare chan "sky", with a short vowel, written as cha-na). If the nucleus of the syllable was itself i, however, the word-final vowel for indicating length was -a: tziik- "to count; to honour, to sanctify" was written as tzi-ka (compare sitz' "appetite", written as si-tz'i).

• Gemination
• Length (phonetics)