Acoustic Features of Mandarin Tone Production in Noise: A Comparison Between Chinese Native Speakers and Korean L2 Learners

Research on Lombard speech produced by Chinese learners remains underdeveloped. This study investigates how native Chinese Mandarin speakers and Korean second language (L2) learners adjust the production of lexical tones under noise conditions. Fifty-two participants (26 Chinese native speakers and 26 higher-level Korean L2 learners) produced 28 syllables under three conditions: babble noise 80 dB SPL, white noise 80 dB SPL, and quiet. Acoustic features, including intensity, duration and F0 contours were analysed. Results indicated that Korean L2 learners significantly increased both intensity and duration across all four tones in the two noise conditions, whereas Chinese native speakers significantly increased durations only for Tone 3 and Tone 4 under white noise. Both groups adjusted F0 contours for all tones in noise, with a notable group difference in the F0 contour of Tone 3. These findings were discussed in association with feedback control theory in second language learners, showing that L2 learners rely more heavily on feedback control and are more detrimentally affected by noise conditions than native speakers.