The role of abstract syntactic knowledge in language acquisition: a reply to Tomasello (2000).

In his paper "Do young children have adult syntactic competence?" Tomasello (Cognition 74 (2000) 209) interprets young children's conservatism in language production as evidence that early language use, and verb use in particular, are based entirely on concrete lexical representations, showing no evidence of abstract syntactic categories such as "verb" or "transitive sentence". In this reply, I argue that Tomasello's interpretation depends on three questionable premises: (a) that anyone with a robust grammatical category of verbs would use new verbs in unattested sentence constructions; (b) that there are no reasons other than lack of syntactic competence for lexical effects in language use; and (c) that children always interpret a new verb presented in the context of an action on an object as a causal action verb, and therefore as one they should use transitively. I review evidence against all of these assumptions. Tomasello's data, among others', show that children indeed learn item-specific facts about verbs and other lexical items - as they must, to become competent speakers of their native language. However, other data suggest that more abstract descriptions of linguistic input also play a role in early language use. To achieve a complete picture of how children learn their native languages, we must explore the interactions of lexical and more abstract syntactic knowledge in language acquisition.