“The Indo-Aryan influence, whether due to actual settlement, acculturation, or, if one prefers, the substitution of Indo-Aryan names for local ones, … - Michael Witzel

This leads to the conclusion that the Indo-Aryan influence, ... was powerful enough from early on to replace local names, in spite of the well-known conservatism of river names. This is especially surprising in the area once occupied by the Indus Civilisation where one would have expected the survival of older names, as has been the case in Europe and the Near East. At the least, one would expect a palimpsest, as found in New England with the name of the state of Massachussetts next to the Charles river, formerly called the Massachussetts river, and such new adaptations as Stony Brook, Muddy Creek, Red River, etc., next to the adaptations of Indian names such as the Mississippi and the Missouri.

Between the arrival of the Aryans ... and the formation of the oldest hymns of the Rigveda a much longer period must have elapsed than is normally thought.

Apparently, Dravidian speakers began influencing the Panjab only at this moment in time. Consequently, all linguistic and cultural deliberations based on the early presence of the Drav. in the area of speakers of IA, are void or they have to be reinvestigated. ... In short, the Panjab is an area of a Pre-rigvedic, largely Para-Munda substrate that apparently overlays a still older local level. Since no traces of the supposedly Dravidian language of the Indus civilization (Parpola 1994) are visible in the early RV (see below), the people who spoke this language must either have disappeared without a trace, or, more likely, the language of the Panjab was Para-Munda already during the Indus period (2600- 1900 BCE). Therefore, the most commonly used language among the languages of the Indus people, at least of those in the Panjab, must have been Para-Munda or a western form of Austro-Asiatic.... In short, even if Drav. had been the traders' language, it remains unexplainable why Drav. influence is only seen in the middle and late RV as well as later one (AV+). The reason cannot be, as van Driem (1999, appendix p. 2, quoting agreement with Parpola) supposes, that the oldest RV hymns were still "composed in more northerly areas, perhaps as far north as modern Afghanistan." (Parpola forthc.) On the contrary, even the oldest books of the RV (4-6) contain data covering all of the Greater Panjab...

None of the archaeologically identified post-Harappan cultures so far found, from Cemetery H, Sarai Kala III, the early Gandhara and Gomal Grave Cultures, does make a good fit for the culture of the speakers of Vedic […] At the present moment, we can only state that linguistic and textual studies confirm the presence of an outside, Indo-Aryan speaking element, whose language and spiritual culture has definitely been introduced, along with the horse and the spoked wheel chariot, via the BMAC area into northwestern South Asia. However, much of present-day Archaeology denies that. To put it in the words of Shaffer (1999:245) ‘A diffusion or migration of a culturally complex ‘Indo-Aryan’ people into South Asia is not described by the archaeological record’ […] [But] the importation of their spiritual and material culture must be explained. So far, clear archaeological evidence has just not been found"