All over the world children learn to understand and speak their own language before they go to school. They (11) this wonderful skill by constant practice, by listening and talk ing all the time to themselves, to their family and friends. At first the child only (12) words and expressions that he has heard and learned. But he finds that he has to put new (13) together to get what he wants. He (14) new sentences out on people. They ac cept some of his sentences but reject others because they are funny or because they don’t (15) The child keeps on trying until he works out a system for producing sentences that can be accept and understood. He gathers in his mind a simple mode of the language, his own grammar of his own language.