Using and encountering multiple languages is the everyday norm of people living in much of the world, including in multicultural cities like Toronto. This course offers a broad exploration of the cognitive and social underpinnings of the dynamic field of bilingualism, multilingualism, and second language acquisition. We will (i) explore the differences between bilinguals/multilinguals and monolinguals in the ways they process and use language; (ii) examine the language acquisition patterns of children and adults; (iii) investigate the interactions between an individual’s language repertoires and those of their peers and local community.