Witzel is apparently secure in his knowledge that (as he put it in his e-mail letter of 3 August 2000): “Nothing of all this is of any importance to … - Shrikant G. Talageri

But Jahnāvī is typically a Rigvedic form of the post-Vedic Jāhnavī, and it does not require any "Epic/Purāṇic concepts" to recognize it as the name of a river: a river is a geographical feature, not a mythological entity whose identity is based on traditional historical or mythological texts. On the other hand, Witzel‘s claim that ―Jahnāvī was the wife or a female relation of Jahnu or otherwise connected to him or his clan is definitely based on Epic/Purāṇic concepts: no person named Jahnu is mentioned anywhere in the Rigveda,...Jahnu himself is an Epic/Purāṇic figure...Not only does Witzel accept this Epic/Purāṇic person as the source of the Rigvedic word Jahnāvī, he even visualizes, in the manner of the Amar Chitrakatha comic books, a mysterious lady named Jahnāvī, "the wife or a female relation of Jahnu or otherwise connected to him or his clan", whose very existence is completely unknown to the whole of Vedic and Epic/Purāṇic literature and Indian tradition, but who is apparently so very important in the Rigveda that she is mentioned twice (how many other ladies are mentioned twice in the Rigveda outside of references to people aided by the Aśvins?) in special references, which are worded so peculiarly (what, after all, unless she was a symbol of the motherland, like the present-day Bhāratmātā, has this lady to do with an ―ancient home), that they can be more conveniently and logically translated as references to a river!

“The modern Indo-Aryan languages are not descendants of the Rigvedic dialects, but of other dialects which were contemporaneous with the Rigvedic dialects, but which belonged to a different section of Indo-European speech (the Inner Indo-European section). The Vedic dialects died away in the course of time, and their speech area [….] was taken over by the Inner Indo-European dialects. But long before they died away, the Vedic dialects had set in motion a powerful wave of a cult movement which covered the entire nation in its sweep. This Vedic cult also finally gave way to the local pan-Indian religion of the Inner-Indo-Europeans and Dravidian-language speakers, but continued to remain in force as the elite layer of this pan-Indian religion” (TALAGERI 1993a:230).

Other scholars, when they deign to notice the evidence in the PurANas in respect of the indigenous origin of the Aryans and their expansion outside India, tend to dismiss this evidence as irrelevant on the ground that it is allegedly contradictory to the evidence of the Rigveda.