Don't apologize. You've done nothing wrong. We're here for you. That's the whole point of being here. Don't worry about your boss. This is a disability. Let's frame it as such from here on out. It's not something you are choosing to do. This is out of your control. How long has the problem been escalating? Any underlying stress or other factors that may be impacting your speech? Stress is a trigger for a lot of us. What steps have you taken to try to improve your speech? Some easy things to try are better sleep and physical exercise. IDK how much these will help, but if stress is a factor, both of these are healthy ways to combat stress. What I always recommend is speech therapy. Even if you've tried it before and it didn't work. Seek out a new SLP who specializes in stuttering and try again. It sounds like you have specific goals you'd like to meet for your job. An SLP may be able to help you. Also, you can go to your boss and tell them you are seeking professional assistance for your disability. This should demonstrate your desire to resolve the problem. I'd ask for financial assistance from your employer as well. SLP's can be expensive. If your employer is unwilling / unable to assist you with your speech therapy goals, that provides you a little cover as well. You're not useless. You have a disability that is debilitating at the moment. The only reason to feel ashamed would be if you fail to take any action to *try* to improve your situation. If you put forth the effort to improve, win or lose, that's something to be proud of. None of this is easy.