People think of us as retards because of our speech impediment and i know some or if not most of us are not but they label us with that. All I can say is Don't try to speak perfectly because no one even folks with no stuttering speak with small and almost negligible blocks and we try to speak perfectly and fluently and that makes our efforts counterproductive. Always relax yes even in times of tense and anxiety relax and just maintain your breath and just let the words come out don't force them. It might not work for everyone so if advise you to watch this video https://youtu.be/5gjPNBugBVg. Take care (Bad english sorry)