Adults who stutter do not stutter during private speech.
Eric S Jackson, Lindsay R Miller, Haley J Warner and 1 others
PMID 34534899WHAT IT FOUND
Twenty-three adults who stutter produced only seven stuttered syllables in over 10,000 syllables of private speech.
This suggests stuttering may be triggered by the perception of a listener rather than the speech mechanism itself.
Key findings
01Participants produced a total of seven stuttered syllables out of 10,844 syllables during the private speech condition.
02Stuttering was significantly lower during private speech compared to when the same utterances were produced with listeners present.
03Speech rate did not differ between private speech and the listener-present condition, ruling out slower speech as the cause of increased fluency.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study used deception to ensure participants believed they were not being observed, which raises ethical and methodological questions about whether participants truly felt alone. The sample size was small (23 participants) and limited to adults with at least moderate stuttering severity. Real-time transcription errors meant that the linguistic content between the private speech and private speech+ conditions was only 64.72% identical, potentially introducing confounds. Whispered and unintelligible speech were excluded from analysis, which may have removed instances of disfluency or altered speech patterns that could affect interpretation.
Declared interests
The research was supported by N.I.H. Extramural funding. The authors declared no conflicts of interest.
The easy way to misread this
Do not interpret this as evidence that isolation cures stuttering or that it is purely psychological. The study demonstrates a correlation between the perception of a listener and stuttering frequency in a controlled lab setting, but it does not test therapeutic interventions or generalize to all daily life situations.