Verbal Pause
The use of words like uh, I mean, you know, and the abominable double pause, I mean you know.
I learned this in a public speaking class I took at the request of my employer to eliminate that abominable double pause. Uh is usually not that bad and even good speakers use it sometimes. The more often they are used, the more atrocious they sound.
I was able to overcome mine, but I can relapse if I am not careful