맞춤법이 어떻게 되요?

(x) What’s the spell? (spell 은 동사)
(o) What’s the spelling?
(o) How do you spell that?

영어 모임을 하고 있어요

(x) I’m in an English study
(o) I’m in an English study group (or I have group study)

사인 해주세요~

(x) May I have your sign? (sign은 동사)
(o) May I have your signature?

여기에 가입하고 싶어요

(x) I want to include in this
(o) I want to be included in this

이건 서비스 입니다.
(x) It’s service
(o) It’s on the house