Regarding the label "disability": In my language, stutter is literally deemed a "_speech handicap_" (there are others, but stutter is one of them). I don't think there's anything wrong with that. It's just a way to describe the problem. Lots of handicaps exist, I see no reason why our stutter couldn't be labeled like that too. Disabilities don't need to be visible or imply something about mental faculties, if that's the assumption.