Harappan language

The Indus script only indicates that it was used to write one language (if any), but it is quite possible that multiple languages were spoken in the IVC, much as Sumerian and Akkadian co-existed in Mesopotamia for centuries. Jane R. McIntosh suggests one such possibility: Para-Munda was originally the main language of the civilization, especially in the Punjab region. Later, the proto-Dravidian immigrants introduced their language to the area in the 5th millennium BC. The Dravidian language was spoken by the new settlers in the southern plains, while Para-Munda remained the main language of those in Punjab.[11]

Michael Witzel suggested as an alternative, that an underlying, prefixing language similar to Austroasiatic, notably Khasi; he called it "para-Munda" (i.e. a language related to the Munda subgroup or other Austroasiatic languages, but not strictly descended from the last common predecessor of the contemporary Munda family). Witzel argued that the Rigveda showed signs of this hypothetical Harappan influence in the earliest historic level, and Dravidian only in later levels, suggesting that speakers of Austroasiatic were the original inhabitants of Punjab and that the Indo-Aryans encountered Dravidian speakers only in later times.[12][13] The theory was since further supported by Franklin Southworth.

As of 2019, Witzel prefers to leave the question of the original Indian language(s) open until better reconstructions for Dravidian and Munda substrate components in Indo-Aryan languages have been done.[14]