On the topic of language, two books that go very well together are Steven Pinker's The Language Instinct and Nicholas Ostler's Empires of the Word: A Language History of the World. The two offer a case study of how historical and scientific approaches to a single subject can complement each other. Despite the comprehensive ambition of each book, there is very little overlap between the two.
Pinker shows what every speaker of a human language has in common, and Ostler considers how and why some languages happen to spread as far as they do. In neither case are the answers as simple as might be naively expected.
Ostler shows why Spanish Jesuits in South America and English Protestants in India had such different linguistic effects, why British Islanders did not end up speaking a Romance language after the fall of the Roman Empire, why English in India and Dutch in Southeast Asia had such different fates, not to mention the parallels between Akkadian and Aramaic, and between Egyptian and Chinese, the Cossacks' conquering of Siberia, and the significance of the Rice Belt.
Pinker summarizes a vast number of scientific studies on how humans process language, including how we can listen and distinguish phonemes at frighteningly fast speeds, how toddlers easily understand features of language that stump any computer program, and various tests of the idea that features of language can be mapped onto features of the mind. Howard Gardner:
Pinker begins by citing a number of common-sense ideas, all of which he promises to demolish in the ensuing chapters. These include the notions that different languages construe reality in different ways; that children learn to talk by imitating others; that grammatical expertise is in steady decline in our society; and that English spelling is uniquely illogical.
There are specific, testable, and built-in syntactical procedures that explain why we say /Darwinian/ and even /Darwinianisms/ but why we would never say /Darwinismian/, why baseball batters "/flied out/" rather than "/flew out/," why we listen to "/Walkmans/" rather than to "/Walkmen/," why hockey players are called "/Maple Leafs/" rather than "/Maple Leaves/," and why even three-year-olds know that a monster who likes to eat mice is a "/mice-eater/" but a monster who likes to eat rats is a "/rat-eater/" not a "/rats-eater/."
Ostler reviews: The Guardian; National Review; ABC Radio; California Literary Review; New Statesman; The Age.
Pinker review: New York Review of Books