I haven't specifically told anyone at work, but I think most people who have spoken to me have figured it out. If they want to ask me about it, I'm not stopping them, but I think people feel uncomfortable bringing it up. But that's their problem. Pretty sure my boss has known from day 1, considering my thesis (which was about stuttering) was part of my portfolio, which was part of my application. Doesn't take much to put two and two together. If you feel like it's going to significantly affect your work, tell someone.