UNESCO Interactive Atlas of the World’s Languages in Danger
Using this map you can look up dead and dying languages throughout the world. This, for example, is a map of languages with 0 (actually 1, since it’s not showing the “extinct” languages) to 100 speakers in Brazil. If you click on the dots or the links at right, you can read some details about the language. Imagine how long it took to compile this data and how quickly it is changing.
[see a different, less blurry screen shot at Good]