This dissertation presents a series of case studies concerned with whether the signal in a given set of measurements that we take in the course of linguistic inquiry reflects grammatical competence or performance factors. We know that performance and competence do not always covary, yet it is not uncommon to assume that measurements that we take…

Non-adult-like linguistic behavior in children is sometimes taken as evidence for endogenous factors that drive selection of grammatical features from the child's hypothesis space of possible grammars. Analyses of English-acquiring children's productions of medial "wh"-phrases exemplify this trend in particular. We provide an alternative…