Hey I know the feeling. I've been stuttering since 4 yrs old and now work as a researcher at a university. I have a BSc in chemistry and MSc in Earth and atmospheric science. Getting my defense done; presenting posters; giving oral presentations; and teaching lab lecture was very difficult. I always prefaced saying "I sutter and if I'm not clear, let me know and I'll try again." Hell at this point I train visiting researcher in our sample preparation techniques and a day didn't go by I don't have to repeat myself. Thankfully most are understanding.