The New York Times reports on new data about how languages diversified:
A researcher analyzing the sounds in languages spoken around the world has detected an ancient signal that points to southern Africa as the place where modern human language originated.
The detection of such an ancient signal in language is surprising. Because words change so rapidly, many linguists think that languages cannot be traced very far back in time. The oldest language tree so far reconstructed, that of the Indo-European family, which includes English, goes back 9,000 years at most.
Quentin D. Atkinson, a biologist at the University of Auckland in New Zealand, has shattered this time barrier, if his claim is correct, by looking not at words but at phonemes — the consonants, vowels and tones that are the simplest elements of language. He has found a simple but striking pattern in some 500 languages spoken throughout the world: a language area uses fewer phonemes the farther that early humans had to travel from Africa to reach it.
I'd like to get more information about this; in particular, how does it account for languages like Basque that seem unrelated to their neighbors?