Hello, Brattania
Honestly, I don't know if "using poor English" exists or is acceptable.
I've heard teachers tell their students to "use English" when they start speaking Spanish in the classroom. But then, those teachers are, like me, Argentinian, and English isn't our first language.
I agree that, strictly speaking, a word or sentence is written using a pen or a pencil. I wouldn't say "using English" myself, but I cannot say I'm sure it's wrong.
Miriam