I'm adding another book to my wish list: "Empires of the Word: a language history of the world" by Nicholas Ostler.
Why? Read this review.
It makes good sense to consider the world from a linguistic perspective. A common language gives people not only a means of communication, but also a peg on which to hang their identity, their shared history and sense of future. Most nation states are recent impositions on top of much older linguistic communities. The Basques have been fighting for years to reunite their ancient linguistic unit, which straddles the borders of modern France and Spain. And Britain and America's "special relationship" is based above all on a shared language.
How have these communities been created? Why have some flourished while others languished? How do languages migrate? Why does a language succeed here but fail there? Why, for example, did Latin leave little trace among the English, while becoming so deeply embedded in the consciousness of other west Europeans that the Romance languages of today - Italian, Spanish, Catalan, Romanian, Portuguese and many more - are less different from Latin than modern English is from medieval English? On the other hand, why was England the only place outside Germany where Anglo-Saxon triumphed so comprehensively?