Language and the brain
Think for a moment of the complex range of computational skills that are involved in understanding and generating language. Yet by the age of 4 or 5 most children can understand language (in their “mother” tongue at least) spoken at a rate of several words per second. This stream of sounds is continuous-not conveniently broken up like words on a page-and the listener has to know the boundaries between words in order to make sense from them. By late adolescence most humans will have a working understanding of many thousands of words (up to 50,000 for English speakers). Humans start to produce language as soon as they begin to acquire their vocabulary. In fact, some psychologists argue that using language precedes knowledge of words, and they cite the verbal-babble interactions of mother and child as examples of pre-vocabulary “speech”.