The augment is a prefix used in certain Indo-European languages, most notably Greek, Armenian and Indo-Iranian languages such as Sanskrit, in the formation of past tenses. Historical linguists are uncertain whether the augment is a feature that was added to some branches of Indo-European or whether the augment was present in the parent language and lost by all other branches (see also Proto-Greek).
In Ancient Greek, the verb ? légo "I say" has the aorist élexa "I said". The initial ? e is the augment. When it comes before a consonant, it is called the "syllabic augment" because it adds a syllable. Sometimes the syllabic augment appears before a vowel because the initial consonant of the verbal root (usually digamma) was lost:
When the augment is added before a vowel, the augment and the vowel are contracted and the vowel becomes long: akoú? "I hear", ?́kousa "I heard". It is sometimes called the "temporal augment" because it increases the time needed to pronounce the vowel.
Unaccented syllabic augment disappeared during the Byzantine period as a result of the loss of unstressed initial syllables. However, accented syllabic augments remained in place. So Ancient , (él?sa, elsamen) "I loosened, we loosened" corresponds to Modern , (élisa, lísame). The temporal augment has not survived in the vernacular, which leaves the initial vowel unaltered: Ancient , ? (agapô, ?gáp?sa) "I love, I loved"; Modern , ? (agapó, agápisa).
|? / dhã||? / dadhãti||? / adhãt||/ adadhãt||put|
|/ gam||/ gacchati||/ agamat||? / agacchat||go|
In J. R. R. Tolkien's Quenya, the repetition of the first vowel before the perfect (for instance utúlië, perfect tense of túlë, "come") is reminiscent of the Indo-European augment in both form and function, and is referred to by the same name in Tolkien's grammar of the language.