People vary widely in the manner in which disfluency appears in their speech. When it comes to filled pauses alone, there are people who use exclusively uh, others who use only um, and still others who seem to mix it up in some way. Some will use them only between utterances, while others (like me) will use them pretty much anywhere. There are some for whom the filled pauses are only long, drawn out articulations, and then there are others (again, like me) who use some filled pauses so quickly that the only way one would notice them is by listening to a recording afterward....

There is some research to show that the use of filled pauses is different in face-to-face versus telephone conversations (cf., high rate of FPs in Switchboard versus low rate in Santa Barbara Corpus). In particular, speakers tend to use more filled pauses on the telephone. It has been hypothesized that the reason for this is that because the visual element is lost, speakers are more apt to try to manage conversational turns through additional vocal elements and thus, they might use filled pauses more often to "hold" their conversational turn. (Leaving aside the debatable question of whether speakers actually use filled pauses in that way or not.) A good question to ask now that video conferencing is becoming a ubiquitous form of communication is whether the use of disfluencies in video-mediated communication differ from those in regular face-to-face communication....