What does the 'critical period hypothesis' propose?

The critical period hypothesis posits that there exists a specific time frame during which language acquisition occurs most successfully and effectively. Research suggests that children have a heightened ability to learn languages and can attain native-like proficiency when exposed to new languages during this optimal developmental window, typically thought to extend from early childhood until around puberty.

This concept is rooted in cognitive and neurological perspectives, which indicate that the brain's plasticity decreases after this critical period, making it more challenging for individuals to achieve the same level of fluency as those who begin learning a language during the optimal age range. This differs from the belief that language learning is effective at any age or that it is impossible to improve language skills after childhood. While it may be more difficult to achieve native-like proficiency later in life, adults can still learn new languages and develop useful communication skills. The idea that only children can acquire a new language flawlessly is also an oversimplification, as some adults can achieve high levels of proficiency with the right methods and circumstances. Overall, the critical period hypothesis emphasizes the importance of age in the process of language acquisition.