My father was the son of immigrants from Poland. My grandfather was a baker, and started a bakery in Detroit. They lived over the bakery, and there was a yard out back. When my father started school, he was bilingual, neither language was English. They put him in second grade because the teacher spoke Polish. He did well and graduated from high school just before he turned sixteen.
I've been in cities where, in a certain area of town, a different language than English was spoken. It takes a while for total assimilation to occur. But it will. As long as we are an accepting culture, not an exclusionary one, they will be assimilated.
