Sanskrit verbs

Based on how the present stem is generated from the verb root, Sanskrit has ten gaṇas (गण) or classes of verbs divided into two broad groups: athematic and thematic. The thematic verbs are so called because an अ a, called the theme vowel, is inserted between the stem and the ending. This serves to make the thematic verbs generally more regular. Exponents used in verb conjugation include prefixes, suffixes, infixes, and reduplication. Every root has (not necessarily all distinct) zero, guṇa (गुण), and vṛddhi (वृद्धि) grades. If V is the vowel of the zero grade, the guṇa-grade vowel is traditionally thought of as a + V, and the vṛddhi-grade vowel as ā + V.

The ten classes were as follows:[3]

Sanskrit roots may also be classified, independent of their gaṇa, into three groups, depending on whether they take the vowel i (इ) before certain tense markers. Since the term used for this vowel by Sanskrit grammarians is iṭ (इट्), these two groups are called seṭ (सेट्, with iṭ), veṭ (वेट्, optional iṭ), and aniṭ (अनिट्, without iṭ) respectively.

It is difficult to generalize how many principal parts a Sanskrit verb possesses, since different verb form categories are used with different degrees of regularity. For the vast majority of verbs, conjugation can be made sufficiently clear with the following forms supplied:

• the present
• the infinitive in -tum, which shows the root in guṇa grade, as well as whether the root uses the connective i. As a result the future tenses are almost always directly formed on this stem.
• the perfect
• the aorist, which for some verbs may include additional distinct middle and passive forms
• the perfect participle in -tas or -nas, which also shows the root in zero grade. On its base are usually formed the gerund and the passive stem.

The gerundive is also irregular, but its use is rather limited and not a basis for any other verb form.

Many verbs are regular enough that only the present and root/infinitive form are needed to derive the entire conjugation. For example, for the aniṭ verb to press, सु su, present सुनोति sunoti, are regularly derived with simple rules:

• the present weak stem sunu-
• the future stem soṣya-
• the perfect stems, from strong to weak suṣāv-, suṣo- and suṣu(v)-
• the aorist stems active asauṣ- and middle asoṣ-
• the perfect participle sutas and the gerund sutvā
• the passive sūya-

All thematic classes have invariant stems and share the same inflectional endings.

The present indicative takes primary endings.

The imperfect takes the augment and secondary endings.

The present optative takes the suffix -e and athematic secondary endings.

The imperative has its own set of special endings. Some of these forms are relics from an original subjunctive.

The present indicative used the strong stem in the singular and the weak elsewhere. For kṛ- used as example here, the weak stem final u is sometimes omitted before endings in v- and m-.

The alternate forms for class 3 (reduplicating class) are shown with hu- 'sacrifice'.

The imperfect uses the two stems in the same way as the present.

The optative takes the suffix -yā in the active, and ī in the middle; the stem in front of them is alway the weak one. Here the final u of the kuru- stem is again irregularly dropped.

The imperative uses the strong stem in all of the 1st person forms, as well as the 3rd person singular active.

The 2nd person active may have no ending (class 5, class 8), -dhi (most of class 3,7, as well as class 1 ending in consonants), or -hi (class 9, class 3 in ā, and class 1 in vowels; these classes usually ended in laryngeals in Proto-Indo-European)

This aorist is formed by directly adding the athematic secondary endings to the root. Originally this type also had different strong and weak stems for the singular and plural, but verbs that both allow this distinction and utilize this type of aorist are exceptionally rare.

From gam- 'go' and dā- 'give' ; the latter takes -us in the 3rd person plural.

Known instances of weak stems from the Veda include avṛjan from vṛj- in the plural active, adhithās from dhā- in the singular middle, and various forms from kṛ- . Middle voice forms of this class are almost nonexistent in the classical period, being suppleted by those of the sibilant classes.

This class is formed with a thematized zero-grade root, and takes regular thematic endings.

From sic- 'pour':

This is the most productive aorist class for regular aniṭ verbs, made by suffixing s to the root. All active voice forms use the vṛddhi grade, and middle forms use the weakest grade that produces a heavy root syllable; kṛ- and some verbs in ā may irregularly uses zero grade in place of the latter.

From jī- 'win':

From tud- 'strike':

This aorist form contains the suffix -iṣ and is the productive form of regular seṭ verbs. The strong active stem is usually strengthened until the root syllable is heavy, and the weak middle stem usually assumes the guṇa grade. Some verbs in a followed by a single consonant, such as grah- , do not take additional strengthening in the active.

From pū- 'cleanse':

This small class is characterized by a reduplicated -siṣ suffix, and is only used in the active voice; the s-aorist is usually used in the middle by verbs that take this formation.

From yā- 'go':

This formation is used with a small number of verbs ending in consonants which can form the cluster kṣ when an s is added. It takes a mixture of thematic and athematic endings.

From diś- 'show':

Past participles are formed directly from verbal roots for most verbs (except for verbs of the tenth gaṇa, which form them from the present stem). They have a perfective sense, in that they refer to actions that are completed. They can freely substitute for finite verbs conjugated in the past sense.

The past passive participle in Sanskrit is formed by adding "-tá" (Kta in Pāṇinian terms), and in some cases "na", to a root in its weakest grade when weakening is applicable (e.g. samprasāraṇa). As expected, the augment "i" is added to the root before the suffix. The resulting form is an adjective and modifies a noun either expressed or implied. The past passive participle can usually be translated by the corresponding English past passive participle: likhitaḥ śabdaḥ "the written word"; kṛtaṃ kāryam "a done deed." See below for more detail and exceptions.

Examples: bhūta from √bhū; kṛta from √kṛ; sthita from sthā (with weakening); ukta from vac (with samprasāraṇa); udita from √vad (with both samprasāraṇa and the i augment); pūrṇa from pṝ (-na in place of -ta and "irregular" root modification).

Depending on the transitivity of the root, the suffix "-tá" has two basic applications: 1. Transitive (sakarmaka) roots: when the suffix -tá is added to a transitive root such as √kṛ "to do," the resulting participle expresses the direct object (karman) of the verbal root. The agent (kartṛ) of the same action must then occur in the instrumental case (tṛtīyā vibhakti) when the speaker wishes to express it.

Example: √han (2P) (to kill)

              राक्षसो हतो रामेण (rākṣaso hato rāmeṇa) = "The demon was killed by Rāma."

Note that rakṣasa is the direct object (karman) of the verbal action expressed in √han "to kill" and the agent (kartṛ) of the same action, Rāma, occurs in the instrumental case.

2. Intransitive (akarmaka) roots: forms adjectives/participles that indicate that the nouns modified are the subjects (kartṛ) for the action of the root (dhātu). This action is frequently in the past. In other words, the participle serves as a nominalization for a simple past tense in the kartari prayoga.

Example: √sthā(1P) (to stand)

             रामो वने स्थितः (Rāmo vane sthitaḥ)  --> Rāma stood in the forest.

These are regularly formed by suffixing -vant to the past passive participles. They modify the subject of the verb from which they are formed.

Unlike the past participles, the present participle is formed from the present stem of the verb, and is formed differently depending on whether the verb is parasmaipada or ātmanepada. The present participle can never substitute for a finite verb. It is also inherently imperfective, indicating an action that is still in process at the time of the main verb.

Formed from the future stem just as the present participle is formed from the present stem, the future participle describes an action that has not yet happened, but that may in the future.

The gerundive is a future passive prescriptive participle, indicating that the word modified should or ought to be the object of the action of the participle.

The perfect participle is a past active participle, but is very rarely used in classical Sanskrit.

The aorist participle used in Vedic was lost in Classical Sanskrit.