Acoustic study in Mandarin-speaking children: developmental changes in vowel production.

BACKGROUND Acoustic analysis had been well incorporated into clinical evaluation and management of children with speech disorders for many years. The aim of this study is to investigate developmental changes in vowel production in Mandarin-speaking children using acoustic study analysis. METHODS A total of 22 children from 5-12 years old were analyzed in this study. Each child read a list of speech materials consisting of 6 dissyllabic words in Mandarin phonemes and the speech samples were recorded. The digitized acoustic recordings were submitted for acoustic analysis. The acoustic parameters in this study include the first and second formant frequencies (F1 and F2) of /a/, /i/ and /u/ and the vowel space. We used the Wilcoxon rank sum test and Spearman's rho correlation test for statistical analysis. RESULTS The F1 values of the vowel /i/ were significantly lower in boys than those in girls (p = 0.013) by Wilcoxon ranksum test. The F1 value of the vowel /i/ was negatively correlated with children's age (rho = -0.601, p = 0.003) and their body height (rho = 0.478 p = 0.045). The F1 values of the other two vowels (/u/ and /a/), the F2 values of all three vowels and the vowel space had no association with age and gender. CONCLUSIONS F1 acoustic parameters have developmental and gender changes in vowel production in Mandarin-speaking children. The data in this study provide references for acoustic assessment of Mandarin-speaking children.