I use a lot of hand gestures when I speak and I prefer video calls over voice-only calls, probably because it allows me to use hand gestures. But I haven't really thought about it, it's just something I do naturally. Any kind of 'reminder device' would feel denigrating, reminding me that I have a stutter and that I am somehow 'different' and 'need fixing'. The device would lower my self-esteem and set me apart from others. I would never use a device like this and would worry that those who do would also feel 'othered'. I think this is a bad idea.