Listeners' uses of um and uh in speech comprehension

Despite their frequency in conversational talk, little is known about how ums and uhs affect listeners' on-line processing of spontaneous speech. Two studies of ums and uhs in English and Dutch reveal that hearing an uh has a beneficial effect on listeners' ability to recognize words in upcoming speech, but that hearing an um has neither a beneficial nor a detrimental effect. The results suggest that um and uh are different from one another and support the hypothesis that uh is a signal of short upcoming delay and um is a signal of a long upcoming delay.