Oh God another terrible trope and I'm not even that far in. Biting your tongue in order to kill yourself is literally impossible. The way you'd die from that is by choking, and your body would most likely prevent you from making yourself choke to death the same way it prevents you from biting your own finger off. You wouldn't bleed out by biting your tongue either. It would clot way too fast. Asian cultures have some really wild mouths, man. I say Asian because this specific one is prevalent in media across various cultures in Asia.