I read somewhere that stuttering can be because of a traumatic event in mostly age group 5-7 or up to 11 ig. And I personally think that's the main reason. I still encounter traumatic events which I can't tell. I told my parents that I stutter because of that. And they say every other household has that. Are u that special? And so on. My 10th board exams were even traumatic. I found it so hard to study that days.