Language Experience Modulates Parallel Acoustic and Phonological Processing of Mandarin Tone: Evidence From Mismatch Negativity

Second-language (L2) speech perception is strongly influenced by prior language experience, but the neural mechanisms supporting this process remain incompletely understood. This study examined how language experience modulates the pre-attentive encoding of acoustic and phonological information in Mandarin tone perception and whether these cues are processed serially or in parallel.

Twenty native Mandarin speakers and 20 novice Mandarin learners with a tonal first language (L1: Thai) completed a behavioral tone identification task and a passive listening multifeature oddball event-related potential paradigm. Stimuli were drawn from an 11-step Tone 1-Tone 2 continuum with Stimulus 5 (S5) as the standard and Stimuli 1, 3, 7, and 9 as deviants. Deviants varied in fundamental frequency distance (large vs. small acoustic distance from S5) and category status (across- vs. within-category) relative to each participant's own phonetic boundary for the continuum. Temporal principal component analysis was applied to separate early and late mismatch negativity (MMN) components.

Behavioral identification did not differ across groups. However, MMN results revealed that both acoustic and phonological factors modulated early and late responses, supporting parallel processing. Native Mandarin speakers exhibited stronger and more sustained phonological effects across both time windows bilaterally. Nonnative speakers showed greater acoustic sensitivity, particularly over the right-hemisphere electrodes, and weaker phonological effects, with reduction most evident over the left-hemisphere electrodes.

The findings show that Mandarin tone perception involves parallel extraction of acoustic and phonological information at the pre-attentive level, with language experience influencing their relative weighting. The neural-behavioral dissociation suggests that tonal L1 experience supports perceptual decisions without fully automatized phonological representations transferred to L2.

https://doi.org/10.23641/asha.34925781.