The document discusses theories of first language acquisition. It describes:
- Children progress through predictable stages of language development in their first years, starting from babbling and cooing to first words and two-word sentences.
- Grammatical morphemes like plurals and verb tenses are acquired in a consistent order cross-linguistically. Children also show understanding of grammar through tests like the "wug test."
- Questions, negation, and word order in questions each have developmental stages as children's language skills increase in complexity.
- Behaviorist theories of language learning, including classical conditioning and operant conditioning, viewed language as learned through stimulus-response associations and reinforcement.