The Vowel That Is Not Written

An abugida spends fewer marks than the sounds it records, and the short a is where the saving is made. A consonant sign is read with this vowel already attached, so a word of three open syllables ending in a can be written with three signs and nothing else. The unit that results is the akshara, the consonant with whatever vowel it carries, and it is the unit Indian tradition counts, recites and uses to measure verse. It is not the letter of an alphabet and it is not quite the syllable of modern phonetics, and the difference is exactly what makes Brahmi and its descendants a family of their own rather than a variant of the alphabets of western Asia.

The independent sign for this vowel therefore has a narrow job. It is written where a word opens with the vowel and nowhere else, so on a page of Brahmi it is uncommon beside the consonant signs. Everything else about the vowel is carried by absence: no mark on a consonant means the inherent a is present, and a mark means it has been replaced. That convention is inherited unchanged by every script descended from Brahmi across South and Southeast Asia, which is why a reader who has learned the principle in one of them can follow it in the rest without learning it again. When a later script wanted to cancel the inherent vowel outright it had to invent a sign for the cancellation, because the script gave it no other way to say that nothing was there.