Evaluation of the voice onset time in Turkish-Speaking schoolchildren

Abstract

ObjectivesTo determine the voice onset time (VOT) values of Turkish speaking schoolchildren and to evaluate the effect of gender, age and vowel height on VOT values in this age group. MethodsOne hundred and twenty native Turkish children between the ages of 7–11 years were included in the study. All children were divided into 4 age groups: Group I 7.0 to 7 years, 11 months; Group II 8.0 to 8 years, 11 months; Group III 9.0 to 9 years, 11 months; and Group IV 10.0 to 10 years, 11 months. The six Turkish plosive sounds (/p/,/b/,/t/,/d/,/k/,/g/) and the eight Turkish vowel sounds (/a/,/e/,/ɯ/,/i/,/o/,/oe/,/u/,/y/) were compiled into 48 different syllables, such as/pa/,/be/,/ti/, and/ko/. The syllables were repeated three times and were recorded by Behringer C-1 studio condenser microphone. Records were analysed by Praat software. The VOT values was established by measuring the time between temporary plosion of the pause and the onset of vocal fold vibration. ResultsThe mean voice onset time values of the voiced and voiceless plosive sounds of the groups were analysed with One Way ANOVA test. There was no statistically significant difference between the groups (p > 0.05). The VOT values of voiceless plosive sounds in all groups were established as positive, and VOT values of voiced plosive sounds were found to be negative. Mean VOT values according to gender was analysed by Independent Samples t-test. A significant difference was found between genders in voiced (/b/,/d/,/g/) plosive sounds and in the/t/sound among the voiceless plosive sounds (p < 0.05). The difference between the heights of vowels and VOT were analysed by one-way ANOVA test. A significant difference was observed between the height of the following vowel and the voiceless plosives/p/,/t/,/k/and voiced plosive/b/(p < 0.05). ConclusionsThe VOT values of voiceless plosive sounds in Turkishspeaking schoolchildren were positive and the VOT values of their voiced plosive sounds were found negative. It was established that the height of the following vowel increases the VOT values of voiceless plosive sounds and has a variable effect on voiced plosive sounds.