Prosodic Structure and Rhythmic Patterns in Zhuang Folk Songs: A Metrical Phonological Perspective

This study systematically examines the prosodic characteristics of Zhuang folk songs, an important intangible cultural heritage of China, to understand interface mechanisms between tonal languages and music. Based on prosodic phonology theory and Optimality Theory, we constructed a large-scale annotated corpus of 1250 Zhuang folk songs from three dialect regions across 12 prefectural-level cities in Guangxi. Using acoustic analysis, statistical modeling, and prosodic annotation, we explored realization patterns of the Zhuang tonal system in singing and its interaction with musical rhythm. The findings reveal systematic tone compression of 0.74 (±0.12) in singing, with a tone retention rate of 68.9%. Level tones show significantly smaller pitch range (38.7 Hz) than in speech (52.4 Hz, t = 8.92, p < 0.001). Prosodic hierarchy-musical beat alignment exhibits gradient characteristics, with prosodic word stress alignment (78.3%) significantly exceeding syllable level (54.6%, F(3,1246) = 87.23, p < 0.001). Tone neutralization occurs more frequently at prosodic boundaries (46.2%) than word-internally (26.8%), with pre-boundary lengthening ratio reaching 1.73 times. Regional analysis shows northern dialect tone retention rate (73.8%) exceeds southern regions (65.4%) by 8.4 percentage points (t = 5.82, p < 0.001), with mixed-effects models confirming significant dialect (β = 0.38) and age effects (β = −0.12). The established prosodic hierarchy constraint model successfully explains coordination mechanisms between linguistic prosody and musical structure in Zhuang folk songs, confirming dynamic balance between tonal integrity and melodic alignment constraints. This research provides new theoretical perspectives for singing prosody in tonal languages and scientific evidence for preserving ethnic minority musical culture.