A question for the native speakers

[Johnny]

Maybe it's better to let the native speakers give us the answer to my following question.

When we talk about a teacher from UK, we generally say English teacher. But when it comes to talking about a teacher who teaches english. we may say english teacher. as least I heard a lot here in China. I know both are working, but they are different in spoken english. The stress depends on what we want to talk about, a person who teaches a subject english or a teacher from an european country UK?

What is the right way to stress to mean it right?

English is a very special word here, what about American then? Like American teacher, meaning a teacher from US ONLY?

Thanks

[Dandelion]

An ENGLISH teacher is any teacher who teaches English.
A BIOLOGY teacher is any teacher who teaches biology.
Why? Because this is a set phrase. The emphasis is on the subject being taught, not the teacher's nationality.

An English TEACHER is from England.
An American TEACHER is from the US.

An ENGLISH book teaches the English language.
An English BOOK can be on any subject, but it comes from England.

[Johnny]

So the word to be stressed has a connection with the meaning. It's easy to understand by your thorough explanation.

Thanks

[Dandelion]

Glad to help.