You are likely to stutter less with someone you perceive as easy-going or understanding. Talking to an authority figure. Speaking to an audience. Many stutterers can read out loud fluently, especially if they don't feel emotionally connected to the book. However, other people only stutter when reading out loud, because they can't substitute words.
Many electronic devices reduce stuttering.
Saying a phrase repeatedly reduces stuttering. Some people can reduce stuttering by trying to stutter, saying that they stutter, or not hiding their stuttering. Some of us, on the other hand, succeed whenever we try to stutter Stutterers can sing fluently. Singing uses continuous phonation and diaphragmatic breathing, like stuttering therapy. Singing uses a different part of the brain than speaking.