It's like the part of the brain that's responsible for language learning is only around early in development and if you don't get your language by then it'll just run out.

就好像负责语言学习的大脑区域,只是在发展的早期比较活跃,如果你没有在这个时候获得语言,那你就没有机会了

耶鲁公开课 - 心理学导论课程节选