I have had similar experiences in some cases worse. My mother was super toxic. I was always scared of her moods. So i kind of grew up learning how not to make her angry. About schools less said the better. The beatings i got were crazy. Developed stuttering in 3rd/4th standard and it continued to get worse until i was 21. However it all changed when i went abroad and started speaking another languge. Now i still stutter in my native language or when i visit back home but when im abroad i dont really notice it. So yeah i do thing enviornament we grow up in might have something to do in developing stuttering.