Hey wofa, that's pretty impressive (over 1000 ums in one lecture)....I can't even begin to match it, but I feel compelled to share with you and ewein (and anyone else who might care!) that I had a math teacher in high school who had two verbal "blips" that were actual phrases:

1. in this case, and
2. in terms of.

He used them so often that a friend and I each picked one and totted up the number of times he used them in a class. He used each phrase over a dozen times in one lesson. We did a "scene" about it for Spanish class, and I still remember the translation for the first phrase (but not, alas, the second):

"en este caso."

On a related note, I once wrote an article for a local magazine about a radio broadcaster. The mag is called Profile Kingston, and it always has three or four profiles of "unsung" Kingstonians (who are then sung? I dunno!). This fellow is a music buff - he had a HUUUUUGE collection of vinyl, tapes and CDs at his apartment (as well as lots of plants - go figger), and he wrote a big thick book all about the history of radio in this area (strange geographical anomaly makes radio frequencies next to impossible to pick up in a certain corridor between Ottawa, our capital city, and Kingston - I think it's to do with the honkin' big rock formation known as the Canadian Shield, but it might also have been to do with the Frontenac Axis). He was telling me about being a broadcaster, and he said, "I never say 'um.' You can learn not to."

Ever since he told me that, I have paid a lot of attention to my own speech - and I do still say "um" but I try to avoid it, particularly when I myself am being interviewed - and to the speech of radio broadcasters, because I'm interested. This feller maintained that it's just lazy and there's no need. I do find it interesting to listen to the radio and hear who "um"s and who doesn't. Those who don't are more compelling to listen to.

Let us go in peace to love and serve the board.