http://www.amazon.com/Language-Instinct-Mind-Creates-P-S/dp/0061336467/ref=sr_1_1?s=books&ie=UTF8&qid=1303447490&sr=1-
A three-year-old toddler is "a grammatical genius"--master of most constructions, obeying adult rules of language. To Pinker, a Massachusetts Institute of Technology psycholinguist, the explanation for this miracle is that language is an instinct, an evolutionary adaptation that is partly "hard-wired" into the brain and partly learned. In this exciting synthesis--an entertaining, totally accessible study that will regale language lovers and challenge professionals in many disciplines--Pinker builds a bridge between "innatists" like MIT linguist Noam Chomsky, who hold that infants are biologically programmed for language, and "social interactionists" who contend that they acquire it largely from the environment.