The linguist Noam Chomsky claims that children are biologically programmed for language and that language develops in the child in just the same way that other biological functions develop. For example, every child will learn to walk as long as adequate nourishment and reasonable freedom of movement are provided. The child does not have to be taught. Most children learn to walk at about the same age, and walking is essentially the same in all normal human beings. For Chomsky, language acquisition is very similar. The environment makes a basic contribution-in this case, the availability of people who speak to the child. The child, or rather, the child's biological endowment, will do the rest. This is known as the innatist position. Chomsky proposed his theory in reaction to what he saw as the inadequacy of the behaviourist theory of learning based on imitation and habit formation (Chomsky 1959).