Some river valleys inhabited by Drokpas, mentioned in the Rig Veda. Probably, formation of Drokpa languages directly adjacent to an area of the Vedic language. In the era of Middle Indian Valley Kabul and the upper Indus undergone expansion of Indo-Aryan Prakriti, and further new Indian languages, Pashto, finally pushed out to the mountains and Drokpa fractured the area into isolated parts. In the mountains Drokpas contacted with the local native languages and gradually assimilated them. Remnants of pre-Indo-population, not assimilated Darden are Burusho people.