The Role of the Sentence-Final Neutral Tone in Mandarin Intonation Perception

Abstract

In tone languages like Mandarin Chinese, fundamental frequency (F0) simultaneously encodes lexical tone and intonation. While previous research has established that intonation is primarily carried by sentence-final full-tone syllables, it remains unclear how intonation is perceived when the final position is occupied by a phonologically weak neutral-tone syllable. The present study addresses this question by using SVO sentences with the sentence-final particle le, whose surface tonal realization depends on its preceding tone. Thirty native Mandarin listeners completed a two-alternative forced-choice intonation identification task (statement versus question) with three stimulus types: original full sentences, truncated sentences (in which le was removed), and switched sentences (in which statement stems were combined with question-final le and vice versa). Results of binomial generalized linear mixed-effects models revealed that in the switched condition, listeners categorized utterances based on the intonation carried by the final le, regardless of the stem-final lexical tone, demonstrating the dominant role of the sentence-final syllable. In the truncated condition, a mirror-image T2-T4 asymmetry was observed: statement stems showed higher consistency when ending with T2, while question stems showed higher consistency when ending with T4. These findings demonstrate that the neutral-tone final syllable serves as the primary perceptual carrier of intonation, while the preceding stem provides compensatory cues that are modulated by lexical tonal trajectories. The T2-T4 asymmetry further supports the functional trade-off hypothesis that when lexical tone and intonation trajectories are congruent, their overlap creates perceptual ambiguity in the absence of the sentence-final particle.