a. Particles: namely, áthā, ádhā, evā́, utā́, ghā́, hā, ihā́, ivā, cā, smā, nā́, an̄gā́, kílā, átrā, yátrā, tátrā, kútrā, anyátrā, ubhayátrā, adyā́, ácchā, ápā, prā́; átī, nī́, yádī, nahī́, abhī́, vī́; ū, tū́, nū́, sū́, makṣū́.
b. Case-forms: especially instr. sing., as enā́, ténā, yénā, svénā, and others; rarely gen. sing., as asyā, hariṇásyā. Cases besides these are few: so símā, vṛṣabhā, hariyojanā (voc.); tanvī̀ (loc.); and urū́ and (not rarely) purū́.
c. Verb-forms ending in a, in great number and variety: thus (nearly in the order of their comparative frequency), 2d sing. impv. act., as pibā, syā, gamayā, dhāráyā; — 2d pl. act. in ta and tha, as sthā, attā, bibhṛtā, jayatā, çṛṇutā, anadatā, nayathā, jīvayathā (and one or two in tana: aviṣṭanā, hantanā); — 1st pl. act. in ma, as vidmā, riṣāmā, ṛdhyāmā, ruhemā, vanuyāmā, cakṛmā, marmṛjmā; — 2d sing. impv. mid. in sva, as yukṣvā, īḍiṣvā, dadhiṣvā, vahasvā; — 1st and 3d sing. perf. act., as vedā, viveçā, jagrabhā; 2d sing. perf. act., vetthā; — 2d pl. perf. act., anajā, cakrā. Of verb-forms ending in i, only the 2d sing. impv. act.: thus, kṛdhī, kṛṇuhī́, kṣidhī́, çrudhī, çṛṇudhī, çṛṇuhī, dīdihī, jahī.
d. To these may be added the gerund in ya (993 a), as abhigū́ryā, ā́cyā.
Vowel-lightening.
249. The alteration of short a to an i or u-vowel in the formative processes of the language, except in ṛ or ar roots (as explained above), is a sporadic phenomenon only.
250. But the lightening of a long ā especially to an i-vowel (as also its loss), is a frequent process; no other vowel is so unstable.
a. Of the class-sign nā (of the krī-class of verbs: 717 ff.), the ā is in weak forms changed to ī, and before vowel-endings dropped altogether. The final ā of certain roots is treated in the same manner: thus, mā, hā, etc. (662–6). And from some roots, ā- and ī- or i-forms so interchange that it is difficult to classify them or to determine the true character of the root.
b. Radical ā is weakened to the semblance of the union-vowel i in certain verbal forms: as perfect dadima from √dā etc. (794 k); aorist adhithās from √dhā etc. (834 a); present jahimas from √hā etc. (665).
c. Radical ā is shortened to the semblance of stem-a in a number of reduplicated forms, as tiṣṭha, piba, dada, etc.: see 671–4; also in a few aorists, as áhvam, ákhyam, etc.: see 847.
d. Radical ā sometimes becomes e, especially before y: as stheyāsam, deya.
