|Einar Meister (Tallinn University of Technology, Estonia), Lya Meister (Tallinn University of Technology, Estonia)|
The paper explores the developmental changes of vowel acoustics in Estonian adolescents as a function of age and gender. Formant frequencies F1–F4 and the duration of vowels were measured from read speech samples of 305 native Estonian subjects (173 girls and 132 boys) aged from 10 to 18 years. GAM framework was applied for the statistical analysis. The results show that both the formant frequencies and the vowel space area decrease gradually from 10 to 15 years in both gender groups and the quality of vowels stabilizes at the age of 15–18 years, whereas gender-specific differences emerge around the age of 12–13. Age-related change in the duration of vowels shows similar patterns with formants, however, with no gender difference. The findings are in line with the results reported for adolescent speech in other languages. The analysis results based on speech samples of the subjects with normal linguistic development can be considered reference data for distinguishing between normal and abnormal speech development.