The poor speak very fast, with quick movements, to attract attention. The rich move slowly and they speak slowly; they don't need to get your attention because they've already got it.
-- MICHAEL CAINE
Inexperienced, unprepared, or nervous speakers often fill their sentences with sounds such as aah, umm, uh, and er. They're known as fillers. Fillers are a way of creating the space to give us time to think. We use them in an attempt to hold onto the listener's attention while we're trying to find the right thoughts and words. Your fillers are saying, "Don't stop listening, I haven't finished yet, just hang on."
It can be terribly irritating when somebody "umms" and "ers" their way through a conversation. You may begin to get a knot in the pit of your stomach or your mind may be saying, "For heaven's sake, get on with it!" Unless you have a particular desire to cling to these peculiar and incomprehensible noises, get rid of them. Nobody likes to hear them; fillers are charm-busters.
The best way to eliminate fillers is to slow down your speaking style and deliberately use more silences. It is as simple as that: If you use silences, fillers disappear. Whatever you do, don't be overly self-conscious in trying to avoid fillers. You don't know where and when they're going to happen. Trying to anticipate an unconscious act could drive you crazy.
Instead, concentrate on using silences every time you feel an "er" or "umm" emerging from your lips. Incorporate silences into your everyday conversations, especially whenever you realize that you are speaking too quickly, and the fillers will take care of themselves.