I went to school in the United States, so I don't know if this would apply where you may be from and/or going to school. To reduce many of the issues regarding my stuttering, I purposely had a letter at the ready that requested an appointment with the professor within the first week of classes. In that letter, it said that I was a stutterer, and would like to not be called upon in class for discussion. This was partly self serving, so that I would not have to speak. I also stressed that there was a definite possibility of making class interaction and exchanges incredibly awkward for the class as a whole if I were to be called on. I said that I did not want to make the class about me, when it is about the course and the professor. Essentially, I did not want to distract from what was being taught. For the most part, the letter never led to a meeting. It stood for itself and the professor would say that they received it and moved on. In the instance where I did meet with a professor, I would have a great relationship with them and alternative methods would be created. I only had one professor that said they would still call on me, but keep it to a minimum. In the United States, stuttering, depending on the severity, would/could be treated as a disability and mitigate any speaking in class. Instead, it created an alternative assignment. If they don't know, they don't know. So be up front and tell them -- especially for smaller classes where there are only 10-20 students and engagement is expected. Keep in mind, I went to college in the late 1990s, so things have come a long way since then. But that was what I did.