Pandya Copper coin with Tamil Brahimi Legend, Karur, First Century B.C. (go the site - mathy)
The chapter on "Language" is a significant part of this book. Mahadevan studied and restudied the inscriptions over and over again and found the confusion was not in them but in the minds of those who read them wrongly. He says, "The argument for the present study is that starting from accurately copied texts and applying the orthographic rules which can be empirically formulated for reading the texts, it can be demonstrated that the language of the cave inscriptions despite the Prakrit loan words, is Old Tamil not materially different from the language of later Tamil inscriptions or even literary texts in its basic phonological, morphological and syntactical features." He made several expeditions to those caves and edited directly from the stone that helped him arrive at this most significant conclusion. Though Br-ahm-i was the mother of all the scripts in India, Devan-agari and Dravidian, it was adapted in a way to suit the genius of the language of the region. There were ! five variations of the Br-ahm-i script such as (1) Northern Br- ahm-i. (2) Southern Br-ahm-i, (3) Bhattiprolu script, (4) Sinhala- Br- ahm-i and (5) Tamil- Br-ahm-i.
Tamil- Br-ahm-i evolved after certain changes were made in Br-ahm-i to suit the phonetic system in the Tamil language.
Tamil- Br-ahm-i omitted sounds not present in Tamil viz., voiced consonants, aspirates, sibilants, the anusv-ara (.m) and the visarga (-h). Tamil has certain sounds for which there were no signs in Br- ahm-i, which called for additional letters viz. -l, .l, -r, -n.
By introducing a diacritical mark called pu.l.li (dots) three things were achieved: (a) basic consonants in final position were indicated (b) ligaturing of consonant clusters was avoided (c) the short vowels `e,' `o' were differentiated from the respective long vowels.