Hesitation Disfluencies in Spontaneous Speech: The Meaning of um

Human speech is peppered with um s and uh s, among other signs of hesitation in the planning process. But are these so‐called fillers (or filled pauses) intentionally uttered by speakers, or are they side‐effects of difficulties in the planning process? And how do listeners respond to them? In the present paper, we review evidence concerning the production and comprehension of fillers such as um and uh , in an attempt to determine whether they can be said to be ‘words’ with ‘meanings’ that are understood by listeners. We conclude that, whereas listeners are highly sensitive to hesitation disfluencies in speech, there is little evidence to suggest that they are intentionally produced, or should be considered to be words in the conventional sense.