Hard truth, nope it never goes away at least not completely and not for majority but it gets manageable and somewhat controllable. I'm 28 now and I've been through some shit, schools didn't have anti bullying policies and one teacher was an asshole, it's a fact that we get to deal with assholes all the time. That being said most of my friends and family don't notice it by now either by being accustomed or due to my natural progression. What helped me was speaking shit and nonsense, hanging out with more people, going out of my comfort zone, literally just reading, most of the time when we (with friends) would order takeout I was the one that had to do calling as a joke but it actually helped me. Also it helps expanding your vocabular to switch to the similar words and for me swearing. Now I'm mostly chill and I speak somewhat slower but I would go through whole day with just a few blocks (and I teach in a school) some people don't even know I stutter. It gets better but you have just go through it, I didn't have any therapy except when I was a child and it didn't help a thing (I needed like whole 5 minutes for two sentences usually)