É correto chamar o professor de Teacher?

Chamar o professor de teacher, na maioria dos casos, é fazer pouco caso do nome dele, é desrespeitoso. O correto é chamá-lo de “Mr + sobrenome”, e das formas mais detalhadas nos exemplos abaixo. Razão? “Teacher” é um título, é o mesmo do que chegar numa empresa e dizer “hey, analista de sistemas!”, em vez de usar o nome da pessoa.

Comentários sobre o assunto na Internet:

“To me, “teacher” is rude, it sounds like you don’t want to take the time to learn their proper name or address them correctly.”

“To merely address your teacher as “teacher” rather than Mr., Mrs, or Miss is quite impersonal… considered somewhat rude!”

“…it’s okay with the teacher, especially if you’re in kindergarten and can’t remember your teacher’s name. No if it’s not okay with the teacher. I would ask first. It may be disrespectful. If the teacher says okay, be ready to be called student, green shirt boy, etc.” (Adorei essa!)

“The use of the word “teacher” in a classroom setting in English-speaking countries may occur only in elementary school but very occasionally, perhaps only in the first few days of the school year, when the little ones haven’t memorized the new teacher’s name yet. Never in high school or elsewhere.”

“This is a typical case of idiomatic contrast and a common interference of Portuguese and for this reason it can easily occur in English schools all over Brazil.”

“(…) All through elementary and secondary school, we say “Mr / Ms So-and-So,” in addressing any teacher. (There’s nothing like “tia” also.) In university, it’s either “Professor, …” or “Mr. So-and-so,…” (when you know s/he doesn’t have a doctorate), or “Dr. So-and-so,…” (when you do know)., but “Professor” for anybody anytime, regardless of degrees. (…)

Ensino pré-universitário: “Professor” is “teacher”, addressed as Mr. or Ms + Last Name.

Universidade: “Professor” is “professor”, always addressed as Mr/Ms/Dr + Last Name or Professor + Last Name.

So you can see why I find it strange to see “teacher Donay.” It wouldn’t be used like that at any level.”

Referência: English Experts