Leg movements affect speech intensity.

Area of Science:

• Motor control and language research
• Biomechanics of speech production
• Interdisciplinary communication studies

Background:

• Previous research suggested speech acoustics and manual gestures are not biologically mandated.
• Recent studies indicate biomechanical entanglement between upper limbs and the respiratory-vocal system.
• Pouw et al. (2021) found high physical impulse in arm movements co-occurred with speech acoustics, suggesting biomechanical coupling.

Purpose of the Study:

• To investigate if the effect of physical impulse on speech acoustics extends to leg motion.
• To explore potential biomechanical links between lower limbs and the speech apparatus.
• To determine if leg movements impact speech acoustics independently of oral communication.

Main Methods:

• Twenty-five German native speakers recalled short stories under three conditions: biking with arms, biking with legs, and static control.
• Acoustic signal analysis focused on intensity peaks and fundamental frequency (F0).
• Analyses mirrored those of Pouw et al. (2021), comparing speech acoustics with leg/arm movement acceleration peaks.

Main Results:

• Intensity peaks in the acoustic signal co-occurred with peak acceleration of leg biking movements.
• This co-occurrence was not observed during arm biking, which showed lower acceleration peaks.
• Fundamental frequency (F0) was not significantly affected by either arm or leg movements.

Conclusions:

• Biomechanical entanglements between the respiratory-vocal system and lower limbs may impact speech production.
• A minimum threshold of physical impulse may be necessary for speech acoustics to be affected.
• Findings challenge the notion of independent control, highlighting potential biomechanical links between legs and speech.