1. There’s several reasons for this. Not only is singing a different part of the brain (more right-hemisphere), it takes some load off of the speech processing centers by providing pre-built intonation patterns, timings, etc, especially if it’s a song you know (as opposed to one you’re learning). 2. This is really up to you. In the United States, disabilities are not explicitly defined by the Americans with Disabilities Act. If you feel that it affects your mental or social well-being, or interferes with work, then yes, you can absolutely count it. I’ve self-identified as having a disability on every job application I’ve filed this year. 3. Yeah this is probably common. I honestly sometimes forget that other people *dont* usually stutter.