Ha! You haven't been to Watsonville, California or just about anywhere along the border with Mexico, have you?
Things tend to be pretty ok in western europe where most can agree on english, but don't forget that a large part of europe was behind the iron curtain and didn't get to learn english until 1989. The majority of people in the east doesn't speak any english at all.
It is only about 60 minutes from Silicon Valley and yet has more culturally and linguistically in common with Mexico in many ways.
The question is not if there are enclaves of other cultures and languages within a larger body of uniform people since on a small enough scale you will always find enclaves: Chinatown, Little Italy, or Kreuzberg in Berlin[2] but how uniform the population is. No population is truly uniform and I don't think anyone pretends that West-Coast Americans and East-Cost Americans are the same as Texan, but I dare to postulate that a common overarching government and a common official language leads to a greater degree of uniformness than 20+ official languages and a loosely knit set of contracts. A norwegian is most likely more different from a greek than a New Yorker from a Californian.
[1] The Sorbs are one of a couple recognized german minorities which explains their special status http://en.wikipedia.org/wiki/Sorbs [2] Strong turkish/arab minority
And I'm sure if you live in Watsonville, California, you can get your tax forms in English, right? This is definitly not the case within the whole of the EU and the EU offical languages. (e.g. someone in Ireland could not get their tax forms in Swedish).
The bigger lesson is, political boundaries suck at defining people or culture.
If you live in a larger urban area in the US, odds are that you can encounter several dozen languages in a day.
However that's not at all like the European Union which has to publish all EU Directives in 23 languages, and each country has 1 or 2 or 3 or 4 official languages for their region. In the USA, English is the lingua franca, and official stuff can be done in English. There is no language that you can use all over the EU that will work in all (or sometimes any) official capacity.
Three to five separate languages per day, as you would encounter in any other moderately multicultural/multinational locale? Yeah, any large urban area will do that.
If I drive 1000 km to the southwest, I'm still in Texas... :) If I wish to drive to the nearest ski resort, I spend most of the drive time getting across the damn state! If I want to hear about 40 different languages, I just go to the nearest shopping mall or to the cafe in the next building.