.
1: “Why can I help you in English?” Does it make sense?– No.
2: “Shoib Akhter has come back to the team.”
3: “Which language is this word?” OR “From which language is this word?”-- (The choice may be only my personal one)
4: transitive verb : to backbite a person (M-W Online)
.
I don’t disagree with Mr. Micawber’s choice for #3, but I personally would be more likely to say “What language is this word” or “What language does _____ come from?”, with ____ being the word in question.