I tried it for a long time. in my experience, it allow you to talk fluently in short conversations and helps when some words that's blocked, at long time I felt it lose it eficiency and can't help you to be completely being fluently, same felling when I talk singing, the diference it was more eficiency to me and awkward to use sometimes cause peoples can notice that you're not speaking normally I ain't a expert in this theme, just someone whose have a stutter so I don't recomend you take my comment as an absolutly true cause it was just something I've experienced, I think there is lots of ways to improve your speech and I'm in my highway to find my life chance one (may vary to person to person). this subreddit is helping me a lot, althought I am a active member I can't help you guys equaly because of my lack of knowedge but I try my best to return the help