Tamil-Brahmi Is Not Brahmi With Three Letters Added

The southern use of the script differs from the northern one in more than its inventory. Tamil-Brahmi handled the inherent vowel differently, and the differences are substantial enough that scholars describe successive orthographic systems within the Tamil-Brahmi material rather than a single practice. In the earliest of them a bare consonant sign is not read with an inherent vowel at all, which inverts the fundamental convention of the northern script, and the vowel that a northern reader would supply automatically is marked instead.

The eventual southern solution was the pulli, a dot placed above a consonant to say that no vowel follows it. That is a genuine innovation and it does the job that the northern scripts later did with a separate vowel-cancelling stroke. Tamil retains it in its modern orthography.

The dating of the earliest Tamil-Brahmi is contested. Proposals have been made on the basis of excavated material at several sites in Tamil Nadu that would place the beginning of the tradition considerably earlier than the conventional account allows, and the arguments turn on archaeological stratigraphy and on radiocarbon determinations rather than on the letters themselves. The atlas records the dispute rather than choosing a side, and an open question states what would settle it.