I have The same thing. Flawless speech alone but bumby road when other join. You can try one thing that works for me. By just telling the People/persons you are talking to helps my stutter. Initiate by telling the person that u stutter often breaks away the anxiety for me. Hi, hello my name is j-o-o-j-o-o.... btw i stutter so bear with me. My name is John, how are you? I would like a Coffee please and I will take it to go, thanks. I have to do this everyday at my local restaurant where i buy my work meals. Im there everyday. Same People behind the counter but still i stutter until i just blurt it out that i stutter. They probably know by now but something in my brain tells me that they dont know and are judging me 😂