Competence versus performance II

Abstract As in Chapter 20, this chapter focuses on the competence/performance distinction and when to attribute non-adult-like performance to a lack of grammatical knowledge, as opposed to unrelated performance failures. It focuses, in particular, on the case of null subjects—when 2-year-olds sometimes omit a sentence’s grammatical subject (e.g., saying eat cookie or came home). One hypothesis is that children “default” to a grammar that permits null subjects, like Spanish, which allows subjects to go unexpressed. This hypothesis is contrasted with performance accounts, on which children have acquired the correct rules for licensing subjects in their language, but other (extragrammatical) factors intervene to cause them to fail to produce overt subjects.