I had never thought of that. How was it received by the audience in your case? I also stutter when I am alone, but less than in public. The question/answer part is definitely stressful. I always feel like people who give talks do not need time to think and can answer very quickly. Someone suggested that for the questions that need more thought, I could leave a notebook where people can write their questions along with their email so I can reply later. I am really impressed by your software idea. It could help a lot of people.