I have interviewed people who do not stutter and I have seen them freeze, panic and fail the most basic tasks. Interviews in general mess people up. Congrats on getting the interview, it proves you have skills relevant to the market. I am sure you will get many more. It sounds like did well in the first half. That's great.  Did anything happen in the second half? Were you less prepared for some of the questions? Did you find yourself rushing? There might be nothing to learn here.  For me, i find if I get flustered it all goes to pot and I can't talk at all. Purposefully pausing helps me a lot to take back control of the pace of the interview and regain control. I wish you the best of luck on the next one!