In my personal opinion, absolutely. In the case you ever may need to speak, 1 - you'll feel better because everyone knows what to expect and won't be confused or asking questions/laughing, etc. And 2 - your teacher can't take off points from disfluency. If you have to present something, and you stutter, the teacher might just think you're a bad speaker and give you a lower grade. Used to happen to me all the time. They aren't allowed to take points away for a speech impediment - it's like taking points off of a deaf kid for not listening. I think you'll feel better in the long run having your teacher know. You can be formal and just explain how it might cause you trouble should you ever need to speak for the class. best of luck, much love