I've been waiting for early news from the US Census on language. And here's some. It's not actually the current Census, of course, but the American Community Survey. (The little article in the link is mostly valuable for the link to the Census report.)
There's plenty of interesting information in the report (check out Appendix A for the history of language questions on earlier censuses), but note for the moment that it gives pretty detailed information on people who don't speak English very well.
One of the most bizarre memes out there among the anti-immigration folks is that Spanish is overrunning English — that English is endangered in parts of this country. If you have heard such stuff, just consider the number of people who report knowing English 'not well' or 'not at all'. Out of 280 million people, 4.5 million report not speaking English at all. (Click on the graphic to see a good version of it.)