There is a detailed article by Eleonora J. Beier, Suphasiree Chantavarin, and Fernanda Ferreira at Psychology and Aging on March 27, 2026 (pages 203 to 218) titled Do Disfluencies Increase With Age? Evidence From a Sequential Corpus Study of Disfluencies. In their fifth paragraph they explain what they focused on:
“Disfluencies have been identified at different levels of production, such as prosodic (e.g., improper stress), lexical (e.g., repetitions), and syntactic (e.g., phrase revisions). Other types of disfluencies include filled pauses (e.g., um, uh), lexical fillers (e.g., well, you know), and silent pauses. In addition, fluency can be assessed by measuring a person’s speech rate, or the speed with which they talk. In this study, we focus on filled pauses (um, uh), repeats (e.g., went to the the store), and repairs (e.g., I think- I believe that …), as well as speech rate.”
The abstract says:
“Speech disfluencies such as repeated words and pauses provide information about the cognitive systems underlying speech production. Understanding whether older age leads to changes in speech fluency can therefore help characterize the robustness of these systems over the life span. Older adults have been assumed to be more disfluent, but current evidence is minimal and contradictory. Particularly noteworthy is the lack of longitudinal data that would help establish whether a given individual’s disfluency rates change over time. This study examines changes in disfluency rates through a sequential design with a longitudinal component, involving the analysis of 325 recorded interviews conducted with 91 individuals at several points in their lives, spanning the ages of 20–94 years. We analyzed the speech of these individuals to assess the extent to which they became more disfluent in later interviews. We found that, with older age, individuals spoke more slowly and repeated more words. However, older age was not associated with other types of disfluencies such as filled pauses (uh’s and um’s) and repairs.
Overall, this study provides evidence that, although age itself is not a strong predictor of disfluencies, age leads to changes in other speech characteristics among some individuals (i.e., speech rate and indicators of lexical and syntactic complexity), and those changes in turn predict the production of disfluencies over the life span. These findings help resolve previous inconsistencies in this literature and set the stage for future experimental work on the cognitive mechanisms underlying changes in speech production in healthy aging.”
And their conclusions are:
“We have presented results from a corpus study of conversational speech to quantify age-related changes in speech fluency sequentially rather than cross-sectionally. We found that older adults spoke more slowly, consistent with previous reports (Castro & James 2014; Gordon et al., 2019; Horton et al., 2010)
and we observed that they produced more repeated words. At the same time, older adults did not produce more repairs or filled pauses, nor was there an effect of age on all three types of disfluencies combined.
Our results show that whether a relationship between age and disfluency is observed depends on the type of disfluency measured, which in turn helps explain previous inconsistent findings. Overall, we suggest that while age is not a strong predictor of fluency measures other than speech rate, there are large individual differences in how other speech characteristics change with age, even in relatively high-functioning older adults, reflecting the trade-off between slower processing speed (Salthouse, 1996; Salthouse & Meinz, 1995) and accumulated vocabulary and language experience (Ramscar et al., 2014). Thus, some individuals slow down their speech as they age—a change associated with higher lexical diversity and the use of less frequent words but also more filled pauses—whereas others do not.
Our findings challenge the prevalent assumption that older age leads to more disfluent speech by showing that other changes in speech production (i.e., overall speech rate, word frequency, lexical diversity, and sentence length) are better predictors of disfluencies than age.”
The cartoon was modified from the center of an image at Wikimedia Commons.











