The evolution of speech and language
Most people feel rather uneasy when reminded that we share 90% of our DNA with our ape ancestors. The idea that we evolved from monkeys was Darwin's most controversial claim in the Origin of the Species, much more unsettling than his hypothesis that the mechanism of evolution was by natural selection; nature red in tooth and claw actually fitted very easily with Victorian beliefs in unbridled capitalism. However, human descent from apes was embarrassing and seemed to denigrate our spirituality, so it was natural to seek ways of distancing ourselves from biology. The most quintessentially human attribute to emphasise was obviously the human ability to communicate by speech and language. Hence, until very recently it was believed that speech was uniquely human. Even chimpanzees, it was thought, could not be taught to communicate beyond rudimentary emotional calls. The power of speech had been bestowed on humans to make us human, all at once by a lucky mutation in the 1% of DNA we do not share with chimps. Chomsky and followers thought that this endowed us with an encapsulated linguistic processing module (Chomsky 1975) and a generative language instinct (Pinker and Jackendoff 2005). © 2007 Springer-Verlag.