Peer-reviewed research

Disfluency rates in conversation: effects of age, relationship, topic, role, and gender

Bortfeld H et al., Language and speech, 2001 · DOI 10.1177/00238309010440020101

Read on October 16, 2026

What it is: A corpus study of task-oriented conversations, in which pairs of speakers described abstract figures or photographs, varying the speakers' ages, roles, relationship and gender. It counts disfluencies such as fillers, repeats and restarts.
How much weight it carries: Peer-reviewed, with a clear corpus design. It studies conversation between people, not dictation or writing, so it is an analogy for spoken language. The url is the Europe PMC record, which carries the abstract.

Facts taken from this source

In a corpus of task-oriented conversations, disfluency rates were higher when speakers discussed abstract figures, which the authors read as an increase in planning difficulty.
“disfluency rates were higher both when speakers acted as directors and when they discussed abstract figures, confirming that disfluencies are associated with an increase in planning difficulty” (Abstract)