Natives would probably be either ignored by a Communist USA, or forced like everyone else onto collectives.
Soviet America may treat natives as 'subversive elements', since unlike Russia the US pre-1980s is really monolingual.
Monolingual? Not hardly.
Before racist immigration quotas were established in the late 20s, every major city in America had neighborhoods full of Polish, Hungarian, Italian, Chinese, Russian, and other immigrants. Each one of these would often have their own stores, their own newspapers (in their language), and more--you could live fairly well only speaking the language of your home country, so long as you didn't stray from that neighborhood.
In parts of the Pacific coast, there were small farming villages where Japanese was used, and English was rare. My own grandparents grew up in a farming village in western Kansas that was more closer to a Swedish town than a typical US one. English was something the kids learned in school, but it wasn't what was used to get a haircut or buy food.
The US started to approach monolingualism in the 50s, I think, when the old generation of immigrants gave way to their "Americanized" children, and no new immigrants were allowed in. But after 1964, we opened the doors again. The US has never been a monolingual English nation.