I feel the same way when it comes to having speech blocks, my past experiences have made me get used to speaking that way which I'm unable to avoid at this point in life. I too want to be a functional adult. I even considered hypnotherapy because I speak fluently when I'm not in situations that make me anxious or when I'm all by myself at home. I've had some bad experiences in life due to my school life and I'm unable to overcome them after these many years. Sometimes even a normal conversation seems difficult due to the blocks. I can relate to you and your situation and I couldn't have explained it any better. I too am looking for ways to get rid of these blocks and the anxiety that causes them.