I.... Don't know. Before I was 18, I had a severe stutter. Then, when I was walking somewhere when a random stranger I passed started a conversation about the weather (Canada. This is normal). And during the conversation, I of course stuttered. But then... Something happened. I got angry. Not at myself, but at the person I was talking to. I didn't say anything to them or act angry, but in my head I was thinking "Yeah, I stutter. What about it?" They didn't even react when I stuttered. It was completely irrational. But, after those few seconds of anger... I stopped caring about my stutter. I never felt another moment of shame about it. And as I cared less about it, I became more fluent. I still have problems with my stutter. Seems to come in waves, where I'll stutter a lot for a few months, and then go long stretches where I don't stutter at all. I've had people know me for months before they realized I had a stutter.