Variation in the choice of filled pause: A language change, or a variation in meaning?

The role of filled pauses in message structuring is a heavily debated question, but the result is still somewhat inconclusive. In this study, I consider this question jointly with sociolinguistic factors that have been thought to affect the choice of filled pause in American English. The results suggest that the use of uh is subject to higher variability across not only age groups, but also conversation topics and interlocutors. A latent semantic analysis found consistent difference between two forms of filled pause and silent pauses of varying duration in the primary latent dimension, but similarity between short silent pause and uh, as well as long silent pause and um in the second dimension. Therefore, the functional difference between um and uh should be acknowledged, and the observed change in their relative popularity is potentially related to their different meaning or function in the discourse.