"[W]hile it would be easy to assume reference to skin colour, this would go against the spirit of the hymns: for Vedic poets, black always signifies evil, and any other meaning would be secondary in these contexts."
Michael Witzel is a German-American philologist, comparative mythologist and Indologist. Witzel is the Wales Professor of Sanskrit at Harvard University and the editor of the Harvard Oriental Series. He has researched a number of Indian sacred texts, particularly the Vedas.
"There is the following direct statement contained in the (admittedly much later) BSS, 1844:3979 sqq which has once again been over-looked, not having been translated yet: ‘Ayu went eastwards His (people) are the Kuru-PancAla and the KASI-Videha This is the Ayava (migration) (His other people) stayed at home in the West His people are the GAndhArI, ParSu and AraTTa This is the AmAvasava (group)’"
"Book 5 [] even knows, in a hymn not suspected as an addition, of the Yamunaa"
"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."
"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."
"Even a brief look at this list indicates that in northern India, by and large, only Sanskritic river names seem to survive.... [he notes that over 90% dont just look IA but] “are etymologically clear and generally have a meaning” [in Indo-Aryan]... [He attributes this unexpectedly large etymological transparency to] “the ever-increasing process of changing older names by popular etymology”. ... [Sindhu might be an] “Indo-Iranian coinage with the meaning ‘border river, ocean’ and fits Paul Thiemes etymology from the IE root *sidh, ‘to divide’”."
"At the outset, it must be underlined that the Vedic texts excel among other early texts of other cultures in that they are tape recordings of this archaic period. They were not allowed to be changed: not one word, not a syllable, not even a tonal accent. If this sounds unbelievable, it may be pointed out that they even preserve special cases of main clause and secondary clause intonation, items that have even escaped the sharp ears of early Indian grammarians. These texts are therefore better than any manuscript, and as good―if not better―than any contemporary inscription" (WITZEL 1999a:3)."