Filler words are the things that get inserted unconsciously in your speech without adding content. They take the place of uncomfortable pauses and act as audio linkages from word to word.
Fillers have been with us forever and no doubt will continue into the future. But if you wish to distinguish yourself as a more professional and credible speaker you should work to find your fillers and eradicate them.
The problem with fillers is that they mutate. You can work diligently to reduce your use of a particular speech affectation only to find a few months later that another vocalization has crept in to take its place.
To be more accurate, somebody you know and trust will have to TELL you that a new filler has become obvious. You will not and cannot hear your own fillers. Even reviewing an audio recording of yourself does not work. Your brain acts as an incredible filter. In exercises I do with clients, they typically spot about half of their own usages, even when explicitly listening for them.
I have noticed that certain filler phrases wax and wane in popularity over the years. Special hall of fame honors go to the perennial favorites "Umm" and "You Know." Those never seem to go out of fashion, and should be high on your targeting radar.
Most people over the age of 40 never use the filler word "Like," but it is a massively intrusive word for the younger population.
In years past, I have noticed temporary upswells in usage of "Actually" and "If You Know What I Mean." But I hardly ever notice them these days.
With 2013 lurching into the final quarter, I feel safe in announcing the winners for this year's trendy fillers. The prize goes to two qualifiers that are basically identical: "Sort Of" and "Kind Of". It was a close battle with similar qualifiers… "I Believe" and "I Think" were right up there, but ultimately lost out to the more generic wishy-washiness of the winning phrases.
Adding qualifiers to your speech conveys several negative connotations for your audience. They may not consciously register these feelings, but will still be swayed by them psychologically. It makes you less authoritative, less of an expert, and less persuasive. It undermines the value and believability of the information you are presenting. And it makes you seem insecure or unsure of yourself as a speaker.
Don't be a trendy 2013 speaker. Take responsibility for what you say. Remove those qualifiers. Then get to work on the other fillers in your speech. If you are interested in a training and behavior modification technique I use, you can go back and read this old chestnut from 2009: "How To Make Enemies And Annoy People."