sentences:  Skinner (1957) claimed that children were not actually learning language per se, instead they were learning about rewards and consequences through the behaviorist theory when they were rewarded for their correct use or language, and punished for incorrect use of language..The Critical period is the first few years of life during which the brain is most sensitive to language learning and development, typically defined to be from age two to puberty.Researchers have found that this can be biologically explained through the maturity of the brain during childhood, leading to a gradual decrease of neuroplasticity in the language areas of the brain up till puberty.