The Language faculty

A review essay on the human visual system can safely presuppose that there is such a system, with homologs in other species, and get on with describing what scientists have learned about how retinal images lead to detailed and informative representations of distal scenes. Discussions of the language faculty are more controversial from the outset. It is not obvious what the alleged faculty does, or whether its operations are specific to language. Indeed, it is not clear what language is, or what languages are. So at least initially, it is hard to say what would make a cognitive system specifically linguistic. Nonetheless, while other animals can communicate to some degree, children go though what seems to be a special kind of linguistic metamorphosis. So in this chapter, we focus on some remarkable facts about how children acquire languages, as a way of gaining insight in this domain. Our conclusion is that humans have a language faculty—a cognitive system that supports the acquisition and use of certain languages—with several core properties. This faculty is apparently governed by principles that are logically contingent, specific to human language, and innately determined. Moreover, at least some of these principles are grammatically pervasive. They are manifested in diverse constructions, and they unify linguistic phenomena that are superficially unrelated. 1 Every biologically normal child acquires thousands of words and a capacity to understand endlessly many complex expressions, given an ordinary and relatively brief course of experience. Indeed, a child can easily acquire more than one language—e.g., Japanese and Mohawk, or English and ASL. As we discuss below, these languages respect certain logically contingent constraints, and each such language is acquirable for the most part by the age of three. This