And this narrowing down is largely in place by about twelve months of age.

这种敏感范围的缩小,大约发生在婴儿十二个月大的时候

耶鲁公开课 - 心理学导论课程节选

You narrow down until you're sensitive just to the language you hear.

你逐渐缩小敏感的范围,直到只对你所使用的语言敏感

耶鲁公开课 - 心理学导论课程节选