You cannot assume that a speaker of English is ipso facto qualified to teach English.

你不能假定会说英语的人就有资格教英语。

《牛津词典》

youdao

We do not teach English by having the students memorize words.

我们教英语时，并不让学生死背单词。

youdao

A question from the teacher. Susanna Wesson writes: "I teach English to French students of engineering who benefit very much from your Foreign Student Series.

VOA: special.2009.05.21

So I did teach English in a foreign country, in Greece for a year, a long time ago.

那么我在外国教过英语，在希腊教了一年，那是在很久以前了。

在公园相遇的老师 - SpeakingMax英语口语达人

which would allow me to teach English in France for a year at a high school.

如果申请成功的话，我可以去法国的高中教一年英语。

耶鲁的著名人士 - SpeakingMax英语口语达人

And they teach English and computer science and ordinary science subjects and mathematics as well.

NPR: Pakistan to Expel Foreign Students at Religious Schools

Schools are starting to teach English as much as Arabic as a second language.

ECONOMIST: Iraqi Kurdistan

"We teach English, maths and science to all students because they are fundamental to understanding society, " she said.

BBC: Technology