First Language Effects on Second Language Perception: Evidence from English Low-vowel Nasal Sequences Perceived by L1 Mandarin Chinese Listeners

First language (L1) sound systems can shape second language (L2) perception of non-native phonological contrasts. This study examines how L1 Mandarin listeners perceive English low vowel + nasal (VN) sequences that are not contrastive in Mandarin. A speeded AX discrimination task tested listeners' low-level processing of English VN sequences, and a perceptual similarity rating task assessed listeners' higher-level phonological knowledge. Despite high discrimination accuracy, reaction times showed that L1 Mandarin listeners had a harder time processing nasal-different sequences compared to L1 English listeners. Moreover, L1 Mandarin listeners perceived vowel-different sequences as more distinct than English listeners. Overall, listeners' L1 phonological system influences L2 perception, suggested by group-level differences in both perceived phonological distinctiveness and phonetic discrimination.