Perceptual assimilation of regionally accented Mandarin lexical tones by native Beijing Mandarin listeners

Pronunciations of Beijing Mandarin are those of Standard Mandarin (hereafter Mandarin), which developed from the Beijing dialect. Native speakers of other regional dialects in China learn Mandarin as an early second language, and produce its four lexical tones (level, rising, dipping, and falling) with regional accents. This study investigated how native Beijing Mandarin listeners perceptually assimilate regionally accented Mandarin lexical tones. Native Beijing Mandarin listeners (M age = 21.31 years) were recruited to identify 16 Mandarin real words (4 consonant-vowel syllables: ba, di, du, gu × 4 tones) produced by speakers of Beijing, Shanghai, and Guangzhou dialects and to rate how similar the productions were to the Beijing accent. Stimuli were blocked by syllable, maintaining minimal contrasts between the tones. The Beijing listeners identified Mandarin words in all three accents with high accuracy (>90%), indicating that they reliably assimilated the regionally accented tones into the four Mandarin tones. However, their reaction times were longer and their rating scores were lower for the regional accents than for the Beijing stimuli. This indicates that while Mandarin listeners are sensitive to accent differences in Mandarin lexical tones, they show phonological constancy across regional accents, which is crucial for tone categorization and discrimination of tone contrasts.