Spectrotemporal Modulation Sensitivity in Speech and Melody Processing Among Mandarin Speakers

Spectrotemporal acoustical markers enable humans to distinguish between speech and song across diverse cultures. Prior research revealed an asymmetric sensitivity in auditory processing: melody perception is more susceptible to spectral degradation, whereas speech sentence perception is more affected by temporal degradation. However, these findings have primarily been based on non-tonal languages, raising questions about how tonal languages, such as Mandarin, might influence these sensitivity patterns. This study investigates how Mandarin speakers process spectrotemporal features in speech and melody, addressing whether tonal language experience modulates the asymmetric spectrotemporal modulation sensitivity patterns observed in non-tonal languages.

Twenty-five Mandarin-speaking participants were recruited in the main experiment to discriminate speech or melody content of Mandarin songs under conditions of varying spectral or temporal degradation. An additional 25 participants in the control experiment listened to degraded hummed melodies or spoken sentences under similar degradation conditions.

Consistent with findings in non-tonal language speakers, Mandarin listeners were more sensitive to temporal degradation in speech and spectral degradation in melody. In addition, they exhibited heightened susceptibility to spectral degradation around 2 cyc/kHz in melody perception, indicating enhanced pitch sensitivity in music, possibly due to tonal language experience. Control analyses revealed reduced sensitivity when hummed melodies or spoken sentences were presented in a single domain, suggesting the influence of cognitive load on auditory processing.

These findings underscore the quasi-universality of spectrotemporal cues in speech and melody perception across languages. However, tonal language experience subtly enhances spectral processing in music, providing new insights into the interaction between speech and music perception across different linguistic backgrounds.