I had a team mate once who would go on and on and on explaining the same point over and over and elaborating a million different ways and it was extremely frustrating because not once would there ever be a break in his speech to give others the chance to ask questions (so he'd explain what we actually didn't understand) or to reply and move the conversation along. It was quite frustrating.
Many of us resorted to talking over him until he noticed, stopped, and let us reply. Surprisingly impervious to interruption.
I had a similar coworker. Worse still because they were a junior who couldn't yield the floor to anyone, regardless of seniority. Their eyes would become a little bewildered as anyone talked over them (read as 'everyone') and they never seemed to grasp what was happening. This piece gives me a better model for understanding them; just a lost soul deep in the church of civility to the point of affliction.
Aren't you saying they're someone who won't yield until they've said their peace? That doesn't sound like the church of civility to me, but more like the rarer "interrupts, but doesn't want to be interrupted" (Barker) style.
Combined with their lack of experience, I can imagine that would be frustrating to be around.
Many of us resorted to talking over him until he noticed, stopped, and let us reply. Surprisingly impervious to interruption.