Sex- and Age-Stratified Normative Voice Data in Mandarin Speakers

Normative voice data for native speakers of Mandarin Chinese have not yet been systematically established in the existing literature. The present study constructed a sex- and age-stratified normative voice dataset based on healthy native Mandarin speakers. On this basis, the vocal characteristics across sex and age were examined using acoustic and physiological measures.

Two hundred participants (Younger Group: 100; Older Group: 100) were instructed to produce the sustained vowels /a/, /i/, and /u/ at their most comfortable pitch and loudness. Acoustic parameters extracted from speech signals included fundamental frequency (F0), jitter, shimmer, harmonics-to-noise ratios (HNRs), cepstral peak prominence (CPP), and spectral measures. Simultaneously, electroglottographic (EGG) signals were recorded to obtain the contact quotient (CQ) and the peak increase in contact (PIC).

The acoustic analyses showed that F0 increased significantly with age in males, whereas it decreased gradually in females. Shimmer was significantly higher in older males than in younger males. Although an increasing trend was also observed in females, the difference was not statistically significant. The older group generally exhibited overall higher values in spectral measures (H1*-H2*, H2*-H4*, H1*-A1*, and H1*-A3*) and noise parameters (HNR15, HNR25, and HNR35) than the younger group. Among these, H1*-H2* and H1*-A1* in females showed distinct patterns across vowels. For EGG measures, both CQ and PIC decreased significantly with increasing age, and a weak negative correlation was found between CQ and H1*-H2*, as well as between CQ and H1*-A3*. The effects of vowel category were also identified: /a/ exhibited the lowest F0 and the highest energy, whereas /i/ showed the highest F0 and the lowest energy. In females, shimmer for the vowel /u/ was significantly lower than for /a/ and /i/, whereas no significant vowel-related differences in shimmer were observed in males.

This study established a normative voice dataset for native speakers of Mandarin Chinese. Building on this dataset, the effects of age, sex, and vowel category on voice quality were systematically investigated. The results indicated that acoustic and EGG parameters demonstrate sex-specific patterns across ages and vowels, with distinct magnitudes observed across age groups. The physiological mechanisms underlying these differences were discussed. The present study provides detailed normative reference data for clinical voice assessment and offers parameter benchmarks for research on non-modal phonations in Mandarin Chinese.