I stutter. My child turned three and started stuttering. There was no reason or event that triggered it. One day he just couldn’t talk. This started about 8 weeks ago. Since then he has gone from a severe weeks where he gets upset and says “I cant do it” and gives up talking to relatively fluent days. We are doing the normal things to help. We are speaking to him in slow clear voices. He has our full attention when he speaks. We give him plenty of time to express himself. His preschool has referred him for therapy. I see some fluent days and I’m hopeful that he will grow out of it. I always wondered if there was a trigger that caused me to start stuttering. After seeing what happened with my son I am now convinced that there is no origin event. I think it is unlikely bad sleep caused this in your child.