Aa: Length as a Distinction That Carries Meaning

Sanskrit measures vowels by duration, and the pairing of a short vowel with its long counterpart is the organising principle behind the opening of the varnamala. A short vowel occupies one mora, a matra in the metrical sense of the word, and a long vowel two; the difference is not stylistic but changes what a word means and what grammatical form it is, so the script needed a way to record it and the vowel signs supply one. Long aa is written after a consonant as a single upright stroke placed to the right of the letter, one of the simplest of the matra signs and the one a learner meets first, since it is also the sign that shows the inherent short a has been replaced rather than merely present.

The independent letter shown here is used only where the vowel opens a word or follows another vowel. Its form is the short letter with the same upright stroke added, a visual logic the script applies consistently: the long member of a vowel pair is usually the short member modified rather than an unrelated shape. Articulation is identical to short a in place, formed in the throat with the tract open, and differs only in the time it is held, which is why the phoneticians treat the two as one vowel quality in two quantities rather than as two sounds. Behind the Devanagari shapes lies a Brahmi ancestor, and Richard Salomon's survey of Indian epigraphy traces the descent of these forms through the inscriptional hands of the intervening centuries.