This means who teaches English and "English" here is a noun (a subject, a language), isn't it ?
For other subjects, we have chemistry teacher, physics teacher, maths teacher...
Can we understand that "English" here is an adjective and "English teacher" is the person whose nationality is English, he/she can teach other subject not English.
How do you think about this ?
Thank you very much !
(1) What a great question.
(2) I think that it depends on how you pronounce it.
(a) Mr. Wong is an ENGlish teacher. His nationality is Chinese,
but he teaches the subject of English.
(b) Ms. Smith is an English teacher. Her nationality is English, but
she actually teaches math.