"We already dealt with this possibility earlier: ‘This may be contrasted with the situation farther east in the Ganga plain, where we do find many Sanskrit-sounding names of rivers and regions which do not have a transparent Sanskrit etymology, for example, kauśikī or kośala, apparently linked to Tibeto-Burmese kosi, “water”, and the name of the river separating Kośala from Videha. In that case, we also see the ongoing sanskritization: kauśikī evolved from kosikī (attested in Pali), and kośala from kosala (idem), which Witzel (1999a: 382) considers as necessarily foreign loans because the sequence -os- is “not allowed in Sanskrit”. But while the phonetic assimilation is caught in the act here, we can see no semantic domestication through folk etymology at work. The name kośala doesn’t mean anything in Sanskrit, and that is a decisive difference with the western hydronyms gomatī, “the cow-rich one”, or asiknī, “the dark one”. While the occurrence of some folk-etymological adaptation among the Panjabi river names could in principle be conceded, it is highly unlikely to be the explanation of all thirty-five names. Until proof to the contrary, the evidence of the Northwest-Indian hydronyms favours the absence of a non-IE substratum, hence of the OIT.’ (Elst 2005:242)"