Another idea from the Mark Kleiman post on immigration enforcement:
Insofar as immigration is legal, we get to set the terms. I'd propose a simple rule: no one comes in who can't speak, read, and write English. I'm not a hard-core assimilationist; I think that Americans tend to under-invest in learning about their ancestral cultures. We all lost something when Yiddish died, and too many Irish-Americans think Tara was where Scarlett O'Hara grew up. But the advantages, to immigrants and to the country, of having our citizens-to-be start out literate in the national language — which is also the world business language — seem to me obvious. As Net access becomes more and more nearly universal, so does access to the tools to learn English up to the rudimentary level which is all we ought to ask for.
The practical effect of this would be to encourage English education in Mexican schools. I have no idea how widespread such classes already are, but given the country's surprisingly high 92% literacy rate, there's clearly some sort of infrastructure for language education, and it's hard to imagine fluency in English would prove anything but an economic boon. The bureaucratic hurdles here are significant, though. Does everyone take a test? Do we rely on the Mexican government's certification procedures? Do we trust those certification procedures?