" our written language " ... well - no - it was created by European missionaries.
No problem.
The far bigger issue is that language groups will only survive long term if based on population bases of millions if not hundreds of millions engaged in modern buisnes and cultures ( English, French, Cantonese, Japanese .... ). Trying to maintain highly local indigenous languages will merely contribute to ongoing isolation - which, if we go by the FN Reserve experience, is not a desired positive outcome.