Has this happened to you? You're walking down the street, minding your own business, when all of a sudden somebody jumps out of a dark alley and shoves a sheet of paper into your hand. You look down and see there's text on it, but you don't recognize the language it's written in. How are you going to figure it out?
Polyglot 3000 is a tool that can take a chunk of text—a page, a paragraph, or maybe even just a single word or two—and tell you which language it's written in. It can recognize nearly 500 different languages and dialects, so your text is probably on their list. European languages, Asian languages, African languages, Native American languages, and more—they're all there; even Esperanto, if you're so inclined (sorry, no Klingon). To speed things up, you can set this app to check only for "popular" languages, or do dive deep and check against the whole database.
Polyglot 3000 is a free download for Windows. And no, I've never had anybody shove a piece of paper like that into my hand either.