The acquisition of wh-questions and the mechanisms of language acquisition

It is no understatement to say that the central issue in the theory of language acquisition is whether children actually learn language and construct a grammar based on the data to which they are exposed, or whether they set the parameters of an autonomous language acquisition device (LAD), which is itself a theory of universal grammar (UG). Some of the arguments which have been taken to be the most compelling for the parameter-setting approach come from two types of cases; 1. the existence of a universal grammatical principle for which there seems to be no evidence available to children in the input, and 2. the production of forms during language development which have no direct model in the adult speech to which children are exposed but which are a possibility sanctioned by UG and which occur in other languages. WH-questions and their acquisition provide important examples of both types and have been cited in the literature as strong evidence in favor of the parameter-setting model (e.g., Chomsky, 1986; Crain, 1991; de Villiers & Roeper, 1991).