I’ve been reading Before the Dawn: Recovering the Lost History of Our Ancestors, by Nicholas Wade. In the section on language he talks about how most areas revert to a mosaic pattern, where there are patches each representing a tribe with its own language. Tribes use language to identify who belongs, and who doesn’t; in other words, who’s a friend and who’s a foe. Those who speak a different language are suspect. Just thinking about how this carries over to modern movements to make English our official language, and how it colors our debates on immigration.