This document discusses three main theories of first language acquisition: behaviorism, innatism, and cognitivism. It provides details on the central ideas of each theory and their main proponents. Behaviorism, proposed by Skinner, views language learning as habit formation through imitation and reinforcement. Innatism, proposed by Chomsky, posits that children are born with an innate language acquisition device that contains universal grammar principles. Cognitivism, associated with Piaget and Vygotsky, sees language as one part of overall cognitive development that involves abstract thinking and social interaction.