The MLA offers an interactive map of the languages spoken in the US -- you can break down the data all kinds of ways:

http://www.mla.org/resources/map_main

That is a cool map.
I find it a little disheartening to see that in hawaii the native language is disappearing and falls into the category of other languages. Although polynesia has such a scattered populace most languages are very similar. All very descriptive and metaphorical (having nowhere near as many words as the english language). I recall dad saying to one of his friends (In Maori) not to pass him those hot stones. Meaning, Don't give me that BS, I'll drop it straight on the ground. The Hawaiian language is just as descriptive as it's dance and it seems sad that so many ideas and proverbs will be lost.
The map shows there is no chance of the english language slowly fading away.