Bidialectal experience affects cue weighting in Mandarin tone perception among older adults

Abstract

It has been observed that older listeners reweight acoustic cues to compensate for age-related sensory decline in speech perception. However, whether the compensation in cue weighting is modulated by lifelong bidialectal experience, a phenomenon found in many older individuals, remains unclear. The present study investigated how bidialectal experience affects Standard Mandarin tone perception among older adults in Shanghai. We compared younger and older Shanghainese-Mandarin bidialectals with monodialectal Mandarin speakers across two experiments. Experiment 1 examined the effects of dialect experience on age-related tone perceptual patterns. Results showed that for older bidialectals, D2-Mandarin tone perception was more resistant to aging than D1-Shanghainese. However, they underperformed monodialectal peers in Mandarin tone identification, indicating potential dialect-specific cue compensatory mechanisms. Experiment 2 further tested this in two tasks by manipulating the acoustic cues (i.e., pitch contour and duration) to create a series of synthetic continua parametrically modeled after the Mandarin T2-T3 contrast. In the phonemic identification task, the older bidialectals showed greater reliance on pitch contours but were less affected by duration cues than the monodialectal group. However, this group difference disappeared in the non-phonemic identification task. Taken together, these findings indicate that lifelong experience with cue weighting in one’s native dialect exerts a top-down influence on tone perception in a second dialect in older adulthood.