Acquisition- North America). Evaluating the Variational Model of Language Acquisition*

proposed by Yang (2002), which claims that all UG-defined grammars are accessible to the learner at the start, and that language acquisition is a process of competition among these grammars. We show that the acquisition of preposition-stranding in English poses a serious challenge to this proposal, and favors the traditional model of parameter-setting. A broader implication is that the time course of language acquisition is a rich source of evidence concerning the mechanisms of parameter-setting. 1