Neural Processing of Phoneme Changes: Differences Between Children and Adults.

PURPOSE: This study examined neural differences in processing of phoneme changes between 5- and 6-year-old Chinese-English bilingual young children and adults using a passive oddball task and event-related potentials. METHOD: Natural speech stimuli with digital refinement were used. Two syllables differing in vowels were manipulated: /da/ (the standard) and /di/ (the deviant). RESULTS: The mismatch negativity (MMN) and P3a were elicited by /di/ relative to /da/ in both the young child and adult groups. However, young children showed a reduced MMN, indicated by smaller mean amplitudes and later peak latencies, compared with adults, although peak-amplitude differences were not statistically significant. Young children also exhibited a significantly enhanced P3a (both mean amplitude and peak amplitude) alongside a delayed peak latency relative to adults. Notably, young children elicited a robust late mismatch response, manifesting as a significant positivity, whereas adults showed no significant response. CONCLUSION: These findings indicate maturational differences in early auditory change detection and involuntary attention orienting during phoneme processing. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.33416941.