원어민 왈 : And the more formal would be "I majored in English Literature." I never really hear anyone say anything about it being undergrad.
ㅎ 스피킹 맥스에서는 인터뷰한 사람이 "I was a psychology major in undergradu."라고 말했는데, 역시 스피킹 맥스!
원어민 왈 : I'd have to say the most colloquial and casual would be just "I was an English Lit major." (Yes, say 'lit' for 'literature'. I hear that all the time.)