We have just studied the pro and contra of some prima facie indications for language contacts which would imply an ancient IE and even PIE presence in Harappan and pre-Harappan India.  In my opinion, none of these can presently be considered decisive evidence for an Indian Urheimat theory, though some of them are indeed suggestive in that direction.

However, to put the strengths and weaknesses of our findings in the proper perspective, we should not forget to also evaluate the evidence from language contacts for the rivalling European Urheimat theory, which should be put to the same tests as the Indian Urheimat theory.  The fact is that such evidence is very scarce, if not non-existent.  The Old-European Basque language has no ancient links with IE.  For the rest, all Old-European languages have disappeared and most have not even survived as dead inscriptional languages providing us with material for linguistic comparison.  Evidence of the type tentatively provided by isoglosses between IE and Semitic, Austronesian or Uralic, all Asian language families, is simply not available for the westerly branches of IE or for a hypothetical Europe-based PIE.  On balance, the evidence from contact with once-neighbouring languages does not provide compelling evidence for an Indian Urheimat (unless the Austronesian connection is valid), but even less evidence for a European Urheimat.

It is too early to say that linguistics has proven an Indian origin for the IE family.  But we can assert with confidence that the oft-invoked linguistic evidence for a European Urheimat and for an Aryan invasion of India is completely wanting.  One after another, the classical proofs of the European Urheimat theory have been discredited, usually by scholars who had no knowledge of or interest in an alternative Indian Urheimat theory.  In the absence of a final judgment by linguistics, other approaches deserve to be taken seriously, unhindered and uninhibited by fear of that large-looming but in fact elusive “linguistic evidence”.