I always thought until now that it was officially considered a disability (in Canada at least, where we are eligible for the disability tax credit). I've been thinking about this a lot and what makes stuttering different from most disabilities is that we are held back by it as the result of other people's actions. We CAN speak, we CAN communicate what we need to just fine – if only people were kinder.  Worst case scenario when we have severe blocks is, we create a pause during a work meeting? which inconveniences no one, certainly not more than a non-stutterer who's very long-winded. So we simply speak differently, in a way that invites false judgement or triggers people's impatience. But because of how prevalent that is, it makes our difference a disability.