It won't matter! Nepali language is like a parasite: it has been spreading slowly and many indigenous people in Nepal don't even speak their native tongue--they can only speak Nepali. There is no need for a national language in Nepal, because if you want to communicate/interact with the mainstream, there is NO OTHER WAY but to speak Nepali. Magars, Rais, Newars, etc have their own language, but they know that most Nepalis speak Nepali as their mother tongue. There is no need to make Nepali Nepal's national language!