The document discusses four main theories of language acquisition: 1) Behaviorism/Imitation theory which views language as learned through imitation, reinforcement, and habit formation. 2) Nativist/Innateness theory which posits that humans are born with an innate language acquisition device that allows them to learn language easily. 3) Cognitive theory which sees language acquisition in the context of cognitive development and links language skills to stages of cognitive maturity. 4) Input theory which focuses on the role of modified "motherese" language input from parents in aiding a child's language acquisition. Each theory is described along with associated thinkers and criticisms.

9. Two distinct views about how LAD functions LAD provides children with a knowledge of linguistic universals such as the existence of word order and word classes LAD provides children only general procedures for discovering language to be learned