"if... or not..."?


“whether… or not…” is quite correct (They didn’t know whether she was right or not), but I just wonder if people ever use “if… or not…” (They didn’t know if she was right or not.

Many thanks

People certainly do.

Prescriptivists will say to use “if” only if there is a possible (if unstated), “then,” and to use “whether” when there is a choice. “See whether he is coming or not” or “See whether he’d like potatoes or rice with dinner.”

But in actual fact, usages like “see if he’s coming or not” or “see if he’d like meatloaf or fried chicken for dinner” are very, very common.