Aspiration, and What a Script Chooses to Say

Brahmi writes aspiration everywhere and consistently, which is a choice, and it is worth setting beside the things the script declines to write. It does not mark the difference between the voiced retroflex stop and the flap it weakens to between vowels. It offers no explicit sign, in its earliest form, for a consonant with no vowel after it. It leaves a good deal of vowel quantity to be recovered from a worn surface. Aspiration it never leaves to the reader, in any period, in any regional hand.

The reason is that aspiration is contrastive across the whole vocabulary in both Sanskrit and Prakrit, so a script that dropped it would produce genuine ambiguity in ordinary words rather than the kind a reader can resolve from context. The features Brahmi leaves unwritten are the ones a competent speaker of the language could supply without effort. That is the ordinary economy of a writing system used by people who already know the language it records, and it is the reason a script developed for its own speakers can look under-specified to a foreign scholar reading it two thousand years later.

The descendant scripts gradually became more explicit as the situation changed. A manuscript tradition copying texts in a language no longer spoken has different requirements from a mason cutting a proclamation for people who speak it, and the additional marks appear as the need for them appears.