I noticed a definite improvement in my speech when I spent a lot of time socializing and going out with friends. I was 10 times more confident than any other point in my life and stuttered much less often. After some unfortunate events caused me to lose my best friend(he didn’t die, we just split) and a year of no longer socializing much, my stutter was even worse than before. I could barely hold a conversation at all. Your speech does improve with practice talking to people. Whether it’s because you become more comfortable in those sorts of situations or because talking a lot forms stronger neural pathways that are involved in speech, idk