Scholars of language development have long been challenged to understand the development of functional categories. Traditionally, it was assumed that children's language development initially relies on lexical elements, while functional elements become accessible only at later periods; and that it is lexical growth which bootstraps grammatical…

The visual-manual modality of sign languages renders them a unique test case for language acquisition and processing theories. In this commentary the authors describe evidence from signed languages, and ask whether it is consistent with Ambridge's proposal. The evidence includes recent research on collocations in American Sign Language that reveal…

The goal of this article is to make the case for a radical exemplar account of child language acquisition, under which unwitnessed forms are produced and comprehended by on-the-fly analogy across multiple stored exemplars, weighted by their degree of similarity to the target with regard to the task at hand. Across the domains of (1) word meanings,…

This article reports on the development and use of the Developmental Sentence Scoring for Japanese (DSSJ), a new morpho-syntactical measure for Japanese constructed after the model of Lee's English Developmental Sentence Scoring model. Using this measure, the authors calculated DSSJ scores for 84 children divided into six age groups between 2;8…