What do you call a person that teaches English in department?

There isn't one specific, universally accepted term for someone who teaches English in a department. The most common terms depend on the context:

General:

* English Teacher: This is the most common and straightforward term.

* Instructor: This is a broader term used for someone who teaches any subject.

* Lecturer: This is typically used for someone who teaches at a university level.

More Specific:

* ESL Teacher: This is used for someone who teaches English as a Second Language.

* EFL Teacher: This is used for someone who teaches English as a Foreign Language.

* TESOL Teacher: This is used for someone who teaches English to Speakers of Other Languages.

* English Language Arts Teacher: This is used for someone who teaches English literature and writing at a high school level.

* Professor: This is used for someone who teaches at a university level and has earned the title of Professor.

The specific term used will depend on the level of education being taught, the specific focus of the English instruction (ESL, EFL, etc.), and the institution where the teaching takes place.