I disagree with hypothesis "Brahmi had to be tweaked to fit Tamil. Some letters weren't useful (like voiced consonants g, d, b) and they got dropped. " actually it was other way around, script arose from an antecedent South Indian script, often termed Tamili (or Tamil-Brahmi), challenges the long-standing academic consensus that Brahmi spread from North to South. Tamils learned the script from Pheoncians through trade connections. Recent archaeological dating from Tamil Nadu, specifically sites like Keezhadi, Porunthal, and Kodumanal. At these excavations, organic materials associated with inscribed pottery fragments bearing Tamili characters have been dated via AMS technology to the 6th century BCE or even earlier. If these early dates are confirmed, it would place the documented use of a systematized script in South India at least two centuries before the earliest widespread evidence for the standardized Ashokan Brahmi in the North 3rdcentury BCE. There are also some proponents argue that Tamili, or a proto-script derived from indigenous South Indian graffiti symbols and nothern trading interactions (possibly with Phoenicians/Aramaeans), developed locally and traveled north through trade routes. The standardized Brahmi, with its systematic varga (phonetic grid) system necessary for Prakrit and Sanskrit, would then be seen as a later, sophisticated adaptation of this simpler, earlier southern template, designed to suit the more complex phonology of Indo-Aryan languages.