Empirical results and formal approaches to recursion in acquisition.

We argue that the move from Direct recursion with conjunctive interpretation to Indirect recursion, where the Strong Minimalist Thesis requires that, at Phase boundaries, a semantic interpretation is necessary, provides the blueprint for the acquisition path. We provide an overview of experimental results AQ1 on the early acquisition (3–4 years) of recursion for PP’s (“on the shelf in the jar”). Adjectives (“big little tractor”) simple compounds (“christmas tree cookie”), and later acquisition (5–7 years) for sentences (“I think you said they gonna be warm”) and verbal compounds (tea-pourer-maker) where language particular factors play a role. Various other factors, branching direction, Relativized MInimality, and morphology must be integrated by the child into the grammatical mechanism. We argue that they cause PP, Adjective, and simple Compounds to be acquired early (3–4 years) and Sentential and Verbal compounds to be acquired late. The fact that subtle steps in acquisition can be captured by very abstract syntactic principles should be seen as a strong source of support for linguistic theory, and an important basis for applied work.