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Anyway those Satavahana inscriptions aren't even in Proto-Dravidian, that's simply Old Tamil, even I can make sense of it.
They were issued in Tamil in a Telugu-speaking region(yes, Telugu had "evolved" by then and had long split from what was to become Tamil) because Telugu had yet to gain official prominence.
ARaHaN and MaKaN aren't words in Telugu to my knowledge, but are present in Tamil. Ironically the first one is from Indo-Aryan.
Sources calling the inscriptions Prakrit and Tamil:
https://books.google.co.in/books?id=...0tamil&f=false
https://books.google.co.in/books?id=...0tamil&f=false
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