The project aims to investigate a radically usage-based approach to the learning of second languages (L2s), including Welsh as an L2. The precise research question will be decided after the initial +1 year. Usage-based theories of language and of language learning have become very influential over the past 15 years, including in explaining first language acquisition. However, its insights have not been widely applied to L2 learning where methodology still follows more traditional understandings of language learning. This project addresses this shortcoming by investigating how fully usage-based L2 learning would work. It is therefore hoped that its findings will be useful in the future design of L2 learning methods.