<Li> The hypothesis places it in the vicinity of Dravidian, perhaps identical with Proto - Dravidian itself . Proposed by Henry Heras in the 1950s, the hypothesis has gained plausibility and is endorsed by Kamil Zvelebil, Asko Parpola and Iravatham Mahadevan . </Li> <Li> Michael Witzel as an alternative suggests an underlying, prefixing language that is similar to Austroasiatic, notably Khasi; he calls 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 argues that the Rigveda shows 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 speakers of Dravidian only in later times . </Li> <Li> a "lost phylum", i.e. a language with no living continuants (or perhaps a last living reflex in the moribund Nihali language). In this case, the only trace left by the language of the Indus Valley Civilization would be historical substratum influence, in particular the substratum in Vedic Sanskrit . </Li> <P> Hypotheses that have gained less mainstream academic acceptance include: </P>

What language was spoken in harappa and mohenjo-daro