When I was in year 1 or 2 so about age 5/6, in my class we answered the register by saying “good morning” to whoever was next in the register to us, I had to say “good morning Grant” and then he would say it to the person next in register to him etc. I never had a problem with it until one day we had a supply teacher, I just completely blocked when trying to say it and sat there blocking then just completely still in fear as everyone around me was saying “just say it!”. My usual teacher knew about my stutter and would’ve skipped me or something or made it not a problem, she was great, but the supply teacher didn’t understand and my class was too young to understand and it was just so awful and embarrassing I sat there and burst into tears lol, have never forgotten it.