I have a perfect command of spoken English.

我的口语掌握得很熟练。

youdao

Japanese children brought up overseas sometimes face great difficulty in adjusting themselves to Japanese schools after returning, even though they have a perfect command of Japanese.

在海外长大的日本孩子虽然能说流利的日文，但他们回国读书的时候，有时也会觉得难以适应新环境。

youdao