It is actually a mystery, cause stutter was a thing since a humans were born, and the fact that there is still no actually a 100% percents working cure says a lot, maybe there would be some cure if people researched more about this disease but they don't, cause only 1% of the people have a stutter and there is no point to research something so insignificant, and i think that it's totally fair, like there are a lot of more serious diseases which must be researched, i got told that it will disappear by itself when i will grow up (I'm 18) but i think it's a lie, like it can't just disappear, it would feel like a magic