fluency

n. 流利

Neither fluency nor accuracy is easy to come by in learning a foreign language.

学习外语要达到流利或精确的程度都是不容易的。

A person who is able to use three languages, especially with equal fluency.

说三种语言的人能够使用三种语言的人，尤指使用三种语言的流利程度相同