This course will focus on the acquisition of two or more languages by both children and adults. We will look at how two or more languages are represented in the mind of an individual and attempt to elucidate the mental processes that allow individuals to produce and understand sentences in each language. Questions that we will consider include: Who is considered bilingual and what are the criteria for 'knowing' a language? How does bilingualism influence linguistic and cognitive development? How does the cognitive system cope with the need to develop efficient processing mechanisms for two or more different languages and maintain separate access and representational mechanisms for each language? How is language is represented in the bilingual brain?