The first stage of combinatorial speech is better described as variable than uniform. Talk of variants obscures two different aspects of language (knowledge and use) and two different aspects of language development -- acquisition of the grammar (competence) and deployment of the grammar in speaking and listening (performance). Null subjects and…

This response argues against the proposal that novel utterances are formed by analogy with stored exemplars that are close in meaning. Strings of words that are similar in meaning or even identical can behave very differently once inserted into different syntactic environments. Furthermore, phrases with similar meanings but different underlying…

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…

This commentary discusses Westergaard's (2021) keynote article, which presents a comprehensive model of first language (L1), second language (L2), and third language (L3) acquisition. The commentary presents evidence from a previous study of L3 learners that provides support for Westergaard's property-by-property transfer proposal. The commentary…