Sneaky Spanish for Americans
Sure, I'd say that to assimilate in America, a person needs to know English. And, all other things being equal, it is better for America to have an immigrant assimilate. The only exception I have thought of would be that rare person with the germn of a timeless idea who will never learn English well enough to express it in that tongue.
But what about the reverse, Americans learning Spanish (and the languages of other immigrants)? If there were a large number of Anglos who could speak Spanish, there wouldn't be so many conversations in Spanish, for example in elevators, which the speakers think are private.
I could probably learn Spanish fairly well.