I hate that line of reasoning. "He's young, he doesn't completely know what he's doing!" Okay, so teach him. Correct his behavior before it becomes a pattern. Don't just let a problem continue. At 14, you're by far old enough to know that a comment is hurtful, especially if someone has told you so many times. A six year old can understand, "Mimicking my speech is rude and hurts my feelings. Please don't do it again." There's no reason why a teenager can't be held accountable for his actions. Is there any way you can have a serious talk with your parents and explain to them how your brother's behaviour makes you feel? Explain to them how him making comments about your speech disorder, something you cannot change, is deeply hurtful. Express to them that is lowers your self esteem, and has even made you contemplate suicide. Also explain that their inaction makes you feel even more helpless. Your brother knows what he's doing, and he knows your parents are letting him get away with it. Let him know it's not okay with you. "I can't help it" "He's only 14, boys will be boys!" You respond, "Do you care that his/your comment was hurtful?" They could respond that you're overreacting or taking it too seriously. You could respond with "Please try to see this from my perspective. I was having difficulty saying something, and my brother laughed at me. I cannot help stuttering, and it's something I'm insecure about. Being laughed at and picked on by my own brother really hurts. I've told you before that it's hurtful. [To your parents] When you defend him, it makes me feel like you don't care about my feelings/[to your brother] when you continue to make comments, it makes me feel like you don't care you're hurting me, or that you want to hurt me." If they continue with justifying your brother's behaviour, or minimizing what he's doing, just leave the room. No matter what you're doing, get up and leave. This goes for each encounter after the initial explanation. If your brother says something, give him a pointed look and leave. Don't even say anything in response. Don't argue with them about whether or not they should respect you. Show them you won't tolerate being disrespected.