First Language Acquisition

Children follow an extraordinary trajectory as they learn their first language. They start in on the speech stream within months, weeks, or even days of birth and break it into manageable pieces. By age one, they have started to associate groups of sounds with meanings and to use them to express their own intentions. In the next several years, they analyze a host of expressions, assign meanings to the parts, and start making use of a larger range of constructions to express their intentions. Another three to four years later, they have attained a vocabulary of close to 14,000 words and are becoming increasingly skillful in how they use language in a range of settings. They have by now mostly mastered the conventional forms for expressing common meanings used in the speech community.

Within acquisition, researchers need to account for both continuity and change in what children know about their first language. This in turn requires us to decide what counts in assessing continuity as well as change. And while most changes move children closer to the conventional patterns of the speech community, it may be harder to identify the developmental links between forms and functions produced at one-and-a-half and at four without scrutiny of the paths children follow. Another factor is general cognitive development, which affects or interacts with their growing skill with language. Finally, we need to specify the general mechanisms children rely on as they acquire language.

Children do not progress in a single bound from identifying the sequence of sounds in bottle to making a request of the form I want my bottle or Can I have some more milk now? To achieve this progression, they apply a variety of procedures. In this chapter, I review some of the ingredients most likely to be required in a general model of language acquisition, and assess the empirical support for them. Critical to this account are two things: the sheer amount that has to be learnt, and the kinds of learning mechanisms required.

Continuity in development

Many systems unfold with development, such that the roots of later forms can be traced to earlier ones. In their capacity to learn, children change enormously between six months and six years. This suggests there could be complex interactions between the learning mechanisms infants start out with and the stages of knowledge those mechanisms are applied to.