[This post was written for a blog I started in 2007 but discontinued soon after. Since that blog no longer exists and the content is relevant here, I've uploaded it here with its original time stamp.]
One of my main research interests is filled pauses in speech (and more recently in writing). I intend to blog a lot about it here, although not exclusively. Nonetheless, in order to get the ball rolling in the context of this blog, I'd like to start by trying to give a definition of a filled pause. This is one of those problems that seems easy at first. For instance, once I say that filled pauses are things like um and uh in speech, then pretty much everybody knows just what I'm talking about (with strong intuitions from their own personal experience). However, when we approach this problem formally, it turns out not to be so easy. I have a hard time coming up with a nice objective definition of a filled pause, because I almost always end up introducing some subjectivity into it. For instance, one possibility might go as follows.
Definition 1: A filled pause is a conventional—though non-word—expression used to stall for time during the processing of spontaneous speech.