Language Development

As noted earlier, language proceeds on a common course for most children. In fact, the weight of the scientific evidence supports the view that children are prewired to learn language. This strong view, however, leaves one pondering the role of input—the language that children are exposed to. Does parental input make no difference in the language development of the child? Can therapists make any difference in correcting language problems if things go awry? A brief review of the role of input in language will help set the record straight and will also provide some feel for the theoretical landscape that guides research in the field of language acquisition at the beginning of the twenty-first century.

First and foremost, it is known that language input must make some difference because all children do not speak the same language. French children will learn French, and Chinese children will learn Chinese. Thus, whatever is built in must be "just enough" to allow children to learn any language and not so much to determine the particular language a child will learn. That input makes some difference is therefore a given. What has been debated, however, is whether this input serves as a trigger for language development or as a mold. On the side of the trigger theories, researchers find that parents do not actively "teach" their children grammar. No parent would ever utter the sentence "I goed to the potty." Yet most parents are overjoyed when they hear this from the child. They do not stop to suggest that the sentence should be "You WENT to the potty."

There is also mounting evidence for those who believe that parents mold language in children. Though parents do not teach children grammar, they do teach children when to say their "pleases" and "thank yous." Further, it is widely accepted that parents who talk more with their children have children who learn more words and use grammar earlier. Input becomes apparent in the limited, but real, individual differences in language development between children.

Language development is the product of an interactive and dynamic system that has components of instinct and of input—of nature and of nurture. The human mind must be built so that young learners selectively attend to certain parts of the input and not to others. With respect to sounds, infants must recognize that the sounds of language are different than the many other sounds that come out of the mouth— sneezes, coughs, and burps do not name objects. In word learning, children must assume that words generally refer to categories of objects, actions, and events. This means that there is not a different name for every table or chair that one encounters in the environment. To learn a grammar, young minds must detect patterns of words but not pay attention, for example, to the syllable structure of every fifth word. Nature provides the starting points for language development, and nurture (the environment) drives the course of that development over time.

Given this interactive view of language, the job for the language scientist of the future is both to identify the selective tendencies of the mind and to see how, in concert with particular inputs, these built-in tendencies allow the child to construct a system that is capable of creating language performances over and over again throughout the course of a human life. The language orchestra, then, is a product of membership in the human species. Humans are given the instruments and the starting points. The language that a person hears around her everyday fine-tunes her sound and helps her build her repertoire. And each child becomes the conductor who pulls all of the components together in a flawless performance that is virtually completed by the time she is three years of age.