Margaret DeucharProfessor Margaret Deuchar’s current research interests are in code-switching. With a research team at Bangor University she collected bilingual conversations from three groups of bilinguals: Welsh-English, Spanish-English and Welsh-Spanish. The conversations were transcribed and are made available in the public domain ( Data from the corpora have been used by Margaret’s collaborators and herself to evaluate competing linguistic theories of code-switching (e.g. Herring et al 2010), to compare code-switching patterns in three bilingual communities (Carter et al 2011), challenge influential views of the boundary between code-switching and borrowing (Stammers & Deuchar 2012) and to establish the key extralinguistic factors influencing the production of code-switching. Margaret is providing advice on developing a framework for data collection and on tagging Welsh corpus data.