"It's also clear from polls that lots of people are upset that Hispanics in the United States 'refuse to learn English,' which would be a legitimate concern except that it's not true: 'Spanish is the primary language among 72% of first-generation Latinos, but this figure falls to 7% among second-generation Latinos and zero among Latinos who are third generation and higher.' The whole idea that this could possibly be a problem is just absurdly ignorant anyway. If you leave the United States, you'll be struck by the fact that huge numbers of people everywhere learn at least some English and would like to learn more. The reason, of course, is that knowing English is a very useful skill. It's even more useful if you actually live in the United States and, what's more, it's obviously much easier for an American-born child of immigrants to learn English than it is for someone growing up in Bangalore or wherever."
What Matt says is especially obvious in the developing world, where English medium schools are considered among the best and parents often pay for children to take English lessons. This article about the Gulf is a recent example, and this is just one of many personal experiences I've had on the subject. I'd never connected it to immigration before, but the key to language development is what people think will benefit them economically. Cultural purity is the primary concern of some intellectuals and people already of high social class.
This also strikes me as silly in part because of work I did as an undergraduate in the old records of the fraternal benefit society called Western Catholic Union. In their early days, they had to produce a lot of materials in German, because that was the only language many of their members could read fluently. German-Americans wound up assimilating just fine.