This won’t come as a big surprise to anyone who isn’t knotted in fear about Hispanics taking over the country, but it turns out that Mexican immigrants are pretty much like every other immigrant population: the longer they’re around, 
the more they speak English. Here is Pew Research:
About three-quarters of Hispanic Millennials are proficient English speakers — that is, they either speak only English at home (28%) or speak a language other than English at home, but speak English “very well” (48%)…. Among Hispanics ages 5 to 17, nearly all of whom are U.S. born, 88% are proficient English speakers, including 37% who speak only English at home and 50% who speak another language at home but speak English very well.
It so happens that I think most liberals give short shrift to fears of official (or effective) bilingualism. My read of history and culture suggests that a common language is a key feature of a unified polity. There just aren’t that many Switzerlands.
That said, there’s not really a compelling reason to do much about this. I may not have any big objections to making English our official language, but why bother? Far from being unique, Hispanics are just like every other wave of immigrants in American history: they start off speaking Spanish, but the second and third generations end up speaking English. And they do it for obvious reasons: they live among English speakers, they watch English-language television, and it’s hellishly inconvenient not to speak it. All we have to do is sit back and do nothing, and Hispanic immigrants will eventually all become English speakers.
