The Family ✨
लङ् — आगम अ + भूत-प्रत्यय
लङ् (Laṅ) — The Augment अ- and Secondary Endings
The imperfect past is built in three steps: (1) take the present stem, (2) prefix अ- (the augment, आगम āgama), (3) add secondary endings. Secondary endings are similar to primary (present) endings but slightly different — note -त् (-t) instead of -ति (-ti) for 3rd sg, and -म् (-m) instead of -मि (-mi) for 1st sg.
Stem Formation
Imperfect formula: अ (a-augment) + PRESENT STEM + SECONDARY ENDINGS Secondary endings (parasmaipada): प्रथम (3rd): -त् · -ताम् · -न् (t / tām / n) मध्यम (2nd): -ः · -तम् · -त (ḥ / tam / ta) उत्तम (1st): -म् · -व · -म (m / va / ma) Compare present endings: -ति/-ताम्/-न्ति vs. imperfect: -त्/-ताम्/-न्
The augment अ- (a-) is the universal marker of past tense in Sanskrit. If a verb already begins with a vowel, the augment merges: a+ā → ā (so √āp → āpnoti present → āpnot... but actually ā+a = ā, so āpnot). For roots beginning with vowels, the augment lengthens that vowel: √ad → present atti → imperfect āt (ā+a = ā). For consonant-initial stems, just prefix a-.