What is the critical period hypothesis in language acquisition?

The critical period hypothesis suggests that there is a specific timeframe during early childhood when the human brain is particularly receptive to acquiring language. This theory indicates that if a child is not exposed to language during this critical window, which typically spans from birth to around puberty, they may never fully acquire a language in its entirety, especially in terms of grammar and pronunciation.

This concept is supported by various observations in linguistics and psychology. For example, children who are isolated from language input during this critical period often struggle to develop fluent language skills later in life, irrespective of the amount of effort or instruction they receive afterward. Thus, the critical period hypothesis emphasizes the importance of timely exposure to language for successful language development, which aligns with option B as the correct answer.

The other options do not accurately reflect the nuances of the critical period hypothesis. For instance, the notion that language can be acquired at any age ignores the empirical evidence supporting the critical period itself. Similarly, suggesting that language learning is purely behaviorally based or exclusively through social interaction doesn't account for the biological and neurological aspects highlighted by the critical period hypothesis, which includes the limitations of cognitive development regarding language acquisition.