From Regular to Context Free to Mildly Context Sensitive Tree Rewriting Systems: The Path of Child Language Acquisition

Current syntactic theory limits the range of grammatical variation so severely that the logical problem of grammar learning is essentially trivialized. Yet, children exhibit characteristic stages in syntactic development at least through their sixth year. Rather than positing maturational delays in the substantive principles of children's grammars, I suggest that acquisition di culties are the result of limitations in manipulating grammatical representations. In particular, I argue that the genesis of complex sentences re ects increasing generative capacity of the systems used to generate structural descriptions: conjoined clauses demand only a regular tree rewriting system; sentential complementation uses a context-free tree substitution grammar; modi cation requires tree adjoining grammar, a mildly context-sensitive system.