World Atlas of Language Structures
Via Language Log: the World Atlas of Language Structures from the Max Planck Digital Library is now freely available online, with Google Maps integration. For example, here’s a map of the velar nasal (?) in Europe. Note the dot for England; that’s the ng in sing. (The strangest sound in English, however, is th.)
Here’s a map of cha vs. te as the source of the word for “tea.” The chapter on writing systems is informative but unfortunately lacks a map.