Usage-based theories of children’s syntactic acquisition (e.g., Tomasello, 2000a) predict that children’s abstract lexical categories emerge from their experience with particular words in constructions in their input. Because modifiers in English are almost always prenominal, children might initially treat adjectives similarly to nouns when used in a prenominal position. In this study, we taught English-speaking preschoolers (between 2 and 6 years) novel nouns (object labels) and adjectives (words referring to attributes) in both prenominal and postnominal positions. The children corrected both postnominal adjectives and nouns to prenominal position, but corrected modifying nouns more often than adjectives. These results suggest that children differentiate between nouns and adjectives even when they occur in the same position and serve the same function (i.e., modification). Children were increasingly likely to correct postnominal adjectives (not nouns) with increasing age. We argue that children attend to word order more when it makes a difference in meaning.

This paper discusses the traceback method, which has been the basis of some influential papers on first language acquisition. The method sets out to demonstrate that many or even all utterances in a test corpus (usually the last two sessions of recording) can be accounted for with the help of recurrent fixed strings (like What’s that?) or frame-and-slot patterns (like [What’s X?]) that can also be identified in the remaining dataset (i.e., the previous sessions of recording). This is taken as evidence that language learning is much more item-based than previously assumed. In the present paper we sketch the development of the method over the last two decades, and discuss its relation to usage-based theory, as well as the cognitive plausibility of its components, and we highlight both its potential and its limitations.

In the usage-based approach to children’s language learning, language is seen as emerging from children’s preverbal communicative and cognitive skills. Children construct more abstract linguistic representations only gradually, and show uneven development in all aspects of their language learning. I will present results that show the relationship between children’s emerging linguistic structures and patterns in the speech addressed to them, and demonstrate the effects played by the consistency of markers, the complexity of the construction in question, and relative type and token frequencies within and across constructions. I highlight the contribution made by research that employs naturalistic, experimental, and modelling methodologies, and that is applied to a range of languages and to variability in the errors that children make. Finally, I will outline the outstanding issues for this approach, and how we might address them.