Let him finish. Stutter or not, when someone seems like pausing in the middle of their speaking and you are feeling an urge to respond or finish their sentence, just look at him first to see what kind of pause that is. If it's a peaceful pause where there is no tension in their body, it's either a thinking pause (they are looking away to think and they are not finished) or a done pause (they are looking at you and they are waiting for you to speak). If there's a tension in their body or in their vocal, it's not really a pause, it's a block and they are not finished. They do not want to be interrupted mid-block. [https://www.youtube.com/watch?v=xilS9aKha10&t=220s](https://www.youtube.com/watch?v=xilS9aKha10&t=220s) In that clip, after she finishes her question, he nods and immediately gets a block and she knows to wait. The tension in his vocal and his hands indicate he's about to say more. If she was a bad interviewer, she would have taken the nod as the full answer and moved on. And if he was anxious as an interviewee, which he wasn't, he would have frozen completely after nodding, which means his hands wouldn't be moving, his eyes wouldn't be moving, his head wouldn't be moving, so it'd look like a done pause. If you are talking with an anxious person, it's good to wait for a few more seconds even after you see what looks like a done pause.