The Effect of Mandarin Vowels on Acoustic Analysis: A Prospective Observational Study

Objectives Although vowels are of interest for acoustic analysis in clinics, there is no consensus regarding the effect of vowel selection on acoustic perturbation parameters. This study aimed to reveal the effects of Mandarin vowels on acoustic measurements. Study Design A prospective observational study. Methods This prospective observational study enrolled normal phonation Mandarin speakers at the Otolaryngology Department of the Eye & ENT Hospital affiliated with Fudan University from December 2020 to August 2021. This study recruited 107 normal-voiced Mandarin speakers (59 women and 49 men) with a median age of 26 (22, 33) years old. The objective measures included traditional acoustic parameters (fundamental frequency, harmonic-to-noise ratio, percent jitter, and percent shimmer) and cepstral analysis (smoothed cepstral peak prominence) of six Mandarin vowels (ɑ /a/, o /o/, e /ɤ/, i /i/, u /u/, ü /y/). Results The acoustic analysis revealed no significant differences in the fundamental frequency among vowels. The low vowel /a/ had the highest values for percent jitter and percent shimmer and the lowest harmonic-to-noise ratio value. The back vowel /u/ had the lowest cepstral measures (P < 0.05). Conclusions The acoustic analysis significantly varied across the different Mandarin vowels, and these differences must be considered for the effective clinical application of objective evaluations.