Bro, I am a stutterer myself, the problem is in your confidence and subconscious and unconscious minds. You need to: 1)Try to make singing you new hobby, then, it will give you awareness on your breathing and diaphragm. 2)Find some cocaine or amphetamine, take it, go to a party, start speaking with everyone there, if this is subconscious or unconscious I swear to god you will not stutter on it, you just will have to remember that feeling what you felt, it should be warm in chest, this is love for yourself, your are the best, you are the man, this should happen. The key is that with 1) you will have a technique to help you reduce the spasm of you physical body with 2) your mind will control itself automatically. And yes I do not say or advice you to become addicted to drugs, if you sniff once nothing bad will happen to you, you just need to believe. I know it sound like matrix but bro, this is it, you is your thoughts, what you think, even if today you told yourself that you are shit, trust me, this deeply sets into you, so only positive. 3)Find some who could put in onto hypnosis state and tell you everything you need to hear to get it deep, that feeling that you are normal. 4)Cold showers like 5 minutes, you will be very calm, you will feel that, the problem is emotions and heartrate, that changes when you stutter, basically you can't understand that you are stressed because you are always stressed. you have to relax. I don't know if it's acquired or congenital, but whatever it is, you are just very stressed and do not understand it, because stress is so normal to you. Control the body, connect it with mind, make new habits, no stutter no stress, good luck.