
Originally Posted by
poi
The mainstream (that I know of at least) is that Prakrit was a later development than Vedic(Sanskrit), just like Classical Sanskrit. I think parasar and client are of the belief that Prakrit might be a completely different branch from RigVedic IndoAryan and even having Mittani-like attributes. Prakrit's -kka -tta do look (to my untrained eyes) similar to how Mittani words are written down, but I would not know beyond that. Anthorin and other linguists here might know more.
As far as Bahuns bringing Prakrit rather than Sanskrit, that would be the opposite. If anything, Nepali Bahuns (if they indeed were independent of the Khas general migration) brought Sanskrit while the Khas (Chettri ancestors) brought the Khaskura(which became Nepali after incorporating Sanskrit vocabulary and TB/Newari/Tamang idioms).
RigVedic version of "Rukh" would be "Ruksa", so Prakrit seems to have lost that "s". You see that quite a bit with later IndoAryan languages where loss of letters. Sanskrit Dakshin is Prakrit Dakkin, etc.
tldr; there is no "Prakrit" influence in Nepali. Nepali IS a Prakrit-derivative. Nepali does have Sanskrit superstrate, likely brought by Bahuns.