一个孩子学习第二语言的最佳时间是已经内化了他或她的母语的年龄。

That means many precious years later than the child's first language.

youdao

一个孩子学习第二语言的最佳时间是已经内化了他或她的母语的年龄。

That means many precious years later than the child's first language.

youdao