In this article we outline the constructivist (or usage-based) approach to children's language development. We argue that linguistic abstractions emerge from the interaction between children's desire to communicate, their intention-reading skills and a distributional analysis of the input. We illustrate our approach by discussing: the development of constituency; inflectional marking; utterance level constructions; more complex syntax in the form of complement-clause structures and relative clauses. We also address explanations for some systematic errors made by English-speaking children that have been much discussed in the literature: optional infinitive errors, accusative for nominative errors and wh-inversion errors. We conclude with some outstanding issues for this approach.