Stuttering frequency on content and function words in adults who stutter: a concept revisited.

This study investigated stuttering frequency as a function of grammatical word type (i.e., content and function). Ten adults who stutter participated. Participants recited aloud a list of 126 words consisting of an equal number of content and function words, which were presented individually and visually via a laptop computer. Each word belonged to a single grammatical category. Further, words were matched for initial sound and approximate number of syllables. The results indicated that adults who stutter exhibited significantly greater stuttering frequency on content words when presented in isolation (p = 0.018). It was conjectured that the responsible factor contributing to differences in stuttering frequency in adults who stutter resides in word frequency disparities between the two classes of words categories. That is, because the function words are limited in number and are used frequently, repeated use on the part of adults who stutter may lead to a generalized adaptation effect for function words and hence reduced stuttering frequency (as compared with content words).