Articulatory and Laryngeal Auditory-Motor Control Are Independent in Tonal Language Speakers

Speech production relies on both the articulatory and laryngeal subsystems. Previous studies on nontonal languages have shown that reflexive and adaptive responses to formant (articulatory parameter) perturbations differ from responses to pitch (or the fundamental frequency [f_o], laryngeal parameter) perturbations, indicating that the articulatory and laryngeal subsystems rely on separate auditory-motor control mechanisms. However, in nontonal languages, formant differences generate lexical distinctions, while laryngeal parameters do not. Thus, it is unclear whether differences between responses to formant and f_o perturbations stem from different linguistic status or distinct auditory-motor control mechanisms. The current study aimed to investigate the relationship between articulatory and laryngeal auditory-motor control in native speakers of Cantonese, a tonal language where both formants and f_o differences alter word meaning.

Adaptive and reflexive responses were measured in 20 native Cantonese-speaking women when receiving predictable and unpredictable auditory perturbations of the first formant (F₁) and f_o.

Similar to nontonal language speakers, no significant correlations were found between F₁ and f_o adaptive responses or F₁ and f_o reflexive responses in Cantonese speakers. We also investigated whether pitch adaptation is achieved by feedforward control incorporating the online feedback reflex and found a significant correlation between reflexive and adaptive responses during f_o perturbation.

The combined findings provide support for independent auditory-motor control mechanisms for articulatory and laryngeal subsystems in tonal language speakers, highlighting the need to study and model articulatory and laryngeal subsystems separately for a more comprehensive understanding of speech motor control.

https://doi.org/10.23641/asha.31245436.