But modern nationalism tends to promote the dominant language of a country above all others. I think it is desirable for immigrants to America to become fluent in English, but we shouldn't accelerate the disappearance of Indian languages that were spoken here pre-1607.
Yes, I agree that the preservation of knowledge of these languages is important. I only criticize attempts to prop up languages when people really have no interest or need of using them in everyday life.
A great deal of that was done in boarding schools in the late 1800s. The children were not permitted to speak their native tongues.