provides the most compelling argument for how language development occurs.

Nineteen fifty-seven was a watershed year in linguistics. Both B. F. Skinner’s Verbal Behavior and Noam Chomsky’s Syntactic Structures were published that year. These books, written by the respective pioneers of the behaviorist and linguistic approaches, placed the source of language development at opposing ends of the spectrum and have provided decades of academic debate. Since then, the number of language development theories has grown exponentially, all with differing ways of explaining language development. Some approaches have confronted serious criticism and undergone revision throughout the decades, and other approaches (e.g., the usage-based approach) are newer and the body of research on them is still limited.