Vowel development in English and Korean: Similarities and differences in linguistic and non-linguistic factors

This study presents an acoustic examination of vowels produced by English and Korean-speaking male and female children in two age groups, 5 and 10 years. In response to picture cards, a total of 80 children (10 each in eight groups categorized according to age, sex and language) produced tokens of seven vowels which are typically transcribed using the same IPA symbols in both languages. Fundamental as well as first and second formant frequencies were measured. In addition, vocal tract length was estimated on the basis of the F3 values of /ʌ/. As expected, these properties differed between the two age groups. However, the two non-linguistic elements (fundamental frequency and vocal tract length) were similar between sexes and between languages whereas the linguistic factors (frequencies of the first and second formants) varied as a function of sex and language. Moreover, the F2 differences between English and Korean-speaking children were similar to those between English and Korean-speaking adults as reported by Yang [Yang, B., 1996. A comparative study of American English and Korean vowels produced by male and female speakers. J. Phonet. 24, 245–261], with children as young as 5 years thus reflecting the formant frequencies of their ambient languages. The results of this study suggest that formant frequency differences between sexes during the pre- and peri-puberty periods can be attributed chiefly to behavioral rather than to anatomical differences.