他的英语很纯正，没有口音。

He can get rid of an accent when speaking English.

youdao

你说英文没有口音。

You speak English without an accent.

youdao

他不仅语言流畅，用词精准，更强大的是完全没有口音。

He is not only fluent in language, precise words, more powerful is completely no accent.

youdao

It is very rare, for instance, for somebody who has learned English past puberty to speak without an accent.

比如,在青春期后才学习英语的人,很少有讲英语是没有口音的

耶鲁公开课 - 心理学导论课程节选

Have you heard of Scouses? No? It's very, very strong.

你听说过利物浦口音吗？没有？这是一种非常非常艰涩的口音。

方言口音很重 - SpeakingMax英语口语达人