Ben Blatt has created a cool series of maps showing what second languages are spoken in the various states of the USA.
Check out the whole article here. I originally read it on Gizmodo, and if you go to that page and read the comments it's quite interesting... many people debating about how common German really is in the US. I, for one, had no idea it was that common. I also had no idea that Tagalog was so common in California...
And so, here are the maps (there are more on the site).
Second most commonly spoken language in the USA after English, by state
Third most commonly spoken language in the USA other than English or Spanish, by state