I once read a story where the hero has a terrible speech impediment. One of his first tasks is to confront a witch. He goes into the swamp and finds her slime covered cavern. She tells him that she is going to test his bravery. He can turn around or submit to the test. He says that he has to go forward.
Is he willing to give up some part of himself, something that defines him and makes him who he is? Fearing he'll lose his face or his memory, he agrees.
She steals his speech impediment.