I can feel it happening before I start speaking. A lot of times I will use language/words to rephrase what I wanted to say so I don't stutter while saying it. If I'm on a zoom call and stutter, I can see my lip, mouth, whatever twitching and it makes me feel self conscious about it but you can feel it. I prefer people NOT to fill in the word I want. For one, it might not be helpful at all - either as a "I'm going to finish your thought and guess even if I'm wrong" OR as a "I hate your stutter or I don't have time for this and will finish it off". This might not be your intention but it's how it might be interpreted. HOWEVER, I'm a regular at a restaurant and I usually order one of two items and always the same drink so I don't mind my waiter/ress finishing off my order or ask if I want X. It makes me feel special and remembered. I struggle on "Medium-well" and hope to god they won't split those up and either do it medium or just well lol I have never mentioned my stutter to others. I'm sure it's very obvious when they hear me speak or introduce myself. I always get stuck on my name so meeting new people is not something I ever do willingly. Be patient and don't rush them. You'll be fine.