• Filler Words
• Discourse Marker
• Dysfluency
• Placeholder
• Repair

Etymology:

Examples and Observations:

• "Fortunately, I'm adhering to a pretty strict, uh, drug, uh, regimen to keep my mind, you know, uh, limber."
  (The Dude in The Big Lebowski, 1998)
• "Um, this is a fairly unique moment both in our, you know, in our country’s history, and, and in, in, you know, my own life, and um, you know, we are facing, you know, unbelievable challenges, our economy, you know, health care, people are losing their jobs here in New York obviously um, ah, you know."
  (Caroline Kennedy, in an interview conducted by Nicholas Confessore and David M. Halbfinger of The New York Times, Dec. 27, 2008)

• "Mrs. Kennedy has managed variously to seem utterly opaque while lacking in the basic skills of plain speaking. There has been not a little mockery of her dependence in conversation on the verbal filler, 'you know.' She was heard to utter it 138 times in a conversation with reporters from The New York Times. In a single TV interview she reportedly galloped past the 200 mark. That's a lot of you knows."
  (David Usborne, "Now Voters Turn Against Kennedy's Stuttering Campaign." The Independent, Jan. 7, 2009)
• "Uh, in a school. And my father, he was, uh, from the United States. Just like you, ya know? He was a Yankee. Uh, he used to take me a lot to the movies. I learn. I watch the guys like Humphrey Bogart, James Cagney. They, they teach me to talk."
  (Al Pacino as Tony Montana in the film Scarface)
• "I've heard about it. I hope you go--you know--I hope you go back to the ranch and the farm is what I'm about to say."
  (President George W. Bush, explaining that he hadn't yet seen the film Brokeback Mountain, Jan. 23, 2006)

• In Defense of Verbal Stumbles
  "Modish public speaking coaches will tell you that it's OK to say 'uh' or 'um' once in a while, but the prevailing wisdom is that you should avoid such 'disfluencies' or 'discourse particles' entirely. It's thought that they repel listeners and make speakers appear unprepared, unconfident, stupid, or anxious (or all of these together). . . .
  
  "But 'uh' and 'um' don't deserve eradication; there's no good reason to uproot them. . . . Filled pauses appear in all of the world's languages, and the anti-ummers have no way to explain, if they're so ugly, what 'euh' in French, or 'äh' and 'ähm' in German, or 'eto' and 'ano' in Japanese are doing in human language at all. . . .
  
  "In the history of oratory and public speaking, the notion that good speaking requires umlessness is actually a fairly recent, and very American, invention. It didn't emerge as a cultural standard until the early 20th century, when the phonograph and radio suddenly held up to speakers' ears all the quirks and warbles that, before then, had flitted by."
  (Michael Erard, “An Uh, Er, Um Essay: In Praise of Verbal Stumbles.” Slate, July 26, 2011)