I knew it!

[The Barbarian]

Imagine standing up to give a speech in front of a critical audience. As you do your best to wax eloquent, someone in the room uses a clicker to conspicuously count your every stumble, hesitation, um and uh; once you’ve finished, this person loudly announces how many of these blemishes have marred your presentation.

This is exactly the tactic used by the Toastmasters public-speaking club, in which a designated “Ah Counter” is charged with tallying up the speaker’s slip-ups as part of the training regimen. The goal is total eradication. The club’s punitive measures may be extreme, but they reflect the folk wisdom that ums and uhs betray a speaker as weak, nervous, ignorant, and sloppy, and should be avoided at all costs, even in spontaneous conversation.

Many scientists, though, think that our cultural fixation with stamping out what they call “disfluencies” is deeply misguided. Saying um is no character flaw, but an organic feature of speech; far from distracting listeners, there’s evidence that it focuses their attention in ways that enhance comprehension.
http://nautil.us/blog/-your-speech-i...cious-messages

The rest is well worth reading. I always thought dysfluencies (a new term for me, and a beautiful word to say) were useful to produce a bit of suspense, pointing to an important part of one's talk. Enough so, that I sometimes introduce dysfluencies when I write, just for that purpose.

But if the research is right, it's even more complex than that. It was most interesting to learn that people designing synthesized voice systems are deliberately introducing dysfluencies to make them more effective.

[Tambora]

I can't stand to listen to a speaker that says "umm" every other sentence.
It IS annoying.

[The Barbarian]

That's not dysfluency; that's a speech impediment.