Analysis of information sources in references of the Wikipedia article "திராவிட மொழிக் குடும்பம்" in Tamil language version.
It is widely suspected that the extinct and undeciphered Indus Valley language was a Dravidian language, but no confirmation is available. The existence of the isolated northern outlier Brahui is consistent with the hypothesis that Dravidian formerly occupied much of North India but was displaced by the invading Indo-Aryan languages, and the presence in the Indo-Aryan languages of certain linguistic features, such as retroflex consonants, is often attributed to Dravidian substrate influence.
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