"“River names in northern India are thus principally Sanskrit, with few indications of Dravidian, MuNDa or Tibeto-Burmese names. However, Kosala, with its uncharacteristic -s- after -o- may be Tibeto-Burmese (Sanskrit rules would demand KoSala or KoSala, a corrected form that is indeed adopted in the Epics).” ... To sum up, what does the evidence of hydronomy tell us? Clearly there has been an almost complete Indo-Aryanisation in northern India; this has progressed much less in southern India and in the often inaccessible parts of central India. In the northwest there are only a few exceptions, such as the names of the rivers GangA, SutudrI and perhaps KubhA.” (p 106-7)"
January 1, 1970
https://en.wikiquote.org/wiki/Michael_Witzel