I'm using voice to text here so I hope this comes through okay but I am a college professor and I am appalled that they would say such a thing yes it is true that in the classroom setting we have time constraints and yes it may make other students uncomfortable but you could preface the entire presentation with a slide that says something like the following (or similar)... I'd also send it to prof in advance to get feedback from them: Hello my name is John Smith and by now some of you probably ave recognized that I have a speech impediment which refer to as a stutter sometimes this manifests as me getting stuck on a certain letter and repeating it a few times other times it manifests as me not being able to say a word at all with occasional awkward causes in my speech. I will likely experience both of these issues during this presentation and I thank you in advance for your patience. You could have this line displayed let them read it and then move ahead with your presentation I think what this will do is it would set the tone but you are fully aware of the situation you know it's going to take you a little extra time that you thank them for being patient this way they are not sitting there uncomfortable while you're trying your best to do your presentation In terms of the college professor asking you not to participate that's like a gym teacher saying they don't want any slow runners participating in a timed run around a track because class has a limited time frame everyone regardless of their situation and conditions should be allowed to participate at the level that they wish to For someone who used to have a horrible horrible stutter which now just manifest typically as blocks and who on a regular basis now stands up in front of audiences of various sizes from a small class of perhaps 15 to an audience of around 200 at presentations it was only through the sheer Act of having to speak in front of people which allowed me to be comfortable speaking in front of people it doesn't happen by itself it doesn't happen in a vacuum it only happens when you actually do it and do it regularly The stutter and the blocks may never go away but your discomfort with doing it will Or at least mine did Wish you luck please report back on how things went I'm very curious