The document discusses various theories of language learning, focusing on the behaviorist perspective which views learning as habit formation through stimulus-response mechanisms, heavily influencing language teaching up to the 1970s. It contrasts this with the innatist perspective, notably advanced by Chomsky, which posits that humans possess an innate understanding of universal grammar that facilitates language acquisition. Additionally, it critiques behaviorism for its limited scope and introduces Stephen Krashen's monitor model emphasizing the importance of comprehensible input and optimal affective conditions in second language acquisition.