Convergence in voice fundamental frequency during synchronous speech

Area of Science:

• Speech Production and Perception
• Acoustic Phonetics
• Clinical Speech Science

Background:

• Joint speech, or speaking in unison, is common and clinically relevant for stuttering therapy.
• It is unknown if synchronous speech timing leads to vocal characteristic alignment, like pitch.
• Understanding vocal alignment during joint speech can illuminate speech motor control mechanisms.

Purpose of the Study:

• To investigate vocal pitch (fundamental frequency, F0) convergence between speakers during synchronous speech.
• To determine if auditory or visual cues influence F0 alignment during joint speech.
• To explore the role of auditory feedback in speech motor control during synchronized speaking.

Main Methods:

• Sixty participants completed two online experiments involving audio recording.
• Participants read sentences individually and then in synchrony with a pre-recorded accompanist voice.
• Conditions included auditory-only, visual-only (silent video), and audiovisual synchrony with the accompanist.

Main Results:

• Significant F0 convergence was observed towards the accompanist's pitch in the auditory-only condition.
• This convergence occurred regardless of whether the accompanist's F0 was higher or lower than the participant's.
• No significant F0 convergence was found in the visual-only condition; audiovisual did not enhance convergence over auditory-only.

Conclusions:

• Auditory feedback is crucial for vocal pitch alignment during synchronous speech.
• Speech motor control models should integrate self- and other-speech feedback interactions.
• Findings offer a new hypothesis for how synchronous speech improves fluency in people who stutter.