Children develop the ability to understand language and to use it to express themselves in the pre-school years. In the school years, these abilities expand and grow. Children also develop more sophisticated metalinguistic awareness. Learning to read gives a major boost to this aspect of language development. Seeing words represented by letters and other symbols on a page leads children to a new understanding that language has form as well as meaning. Reading reinforces the understanding that a `word' is separate from the thing it represents. Unlike three-year-olds, children who can read understand that `the' is a word, just as ‘house’ is. They understand that `caterpillar' is a longer word than `train', even though the object it represents is substantially shorter! Metalinguistic awareness also includes the discovery of such things as ambiguity. Knowing that words and sentences can have multiple meaning gives children access to word jokes, trick questions, and riddles, which they love to share with their friends and family.