Someone who is fluent in a particular language can speak the language easily and correctly. You can also say that someone speaks fluent French, Chinese, or some other language.
双语例句
例：
She studied eight foreign languages but is fluent in only six of them.
她学了8种外语，但能流利运用的只有其中的6种。
例：
He speaks fluent Russian.
他说一口流利的俄语。
2.?流畅的
If your speech, reading, or writing is fluent, you speak, read, or write easily, smoothly, and clearly with no mistakes.
双语例句
例：
He had emerged from being a hesitant and unsure candidate into a fluent debater.