The acquisition, processing and representation of language, focusing on two fundamental questions: what does it mean to know language and how is this knowledge acquired? The learning mechanisms used by children and adults in learning first and second languages; the mechanisms involved in language processing; and the various factors - cognitive and environmental - that influence children's linguistic development. My research lies at the intersection of Linguistics, Psychology and Cognitive Science - it combines theoretical insights from the three fields, and applies experimental methods from the social sciences to the study of language. We draw on a variety of experimental methodologies (among them naturalistic child and adult corpus studies, experiments with children and adults, and artificial language learning), and look at a range of languages (mostly English, Hebrew and Arabic) and populations (child learners, adult native-speakers, and L2 learners.