I do the exact same. My vocabulary is extensive and I use this to my advantage when I can't articulate as I want to. Round table introductions are the worst and the nature of my job requires it often. I've taken to rehearsing a set phrase so as to eliminate a bit of tension..but still comes out awkward... Thankfully I work with a fantastic communicator who is aware of my stutter. Often she will elaborate on my skills and comments and I am very grateful. She's very conscious to not talk over or for me but it's subtle and does me a big favour sometimes.