محسن مددی

The present study explored the effects of voicing and place of articulation on voice onset time (VOT) and fundamental frequency (F0) of onset of Persian oral plosives uttered by normal hearing (NH) and hearing-impaired (HI) children. Twenty-one NH children and twenty-one HI children matched for age and gender took part in this study. The participants were asked to repeat 36 CV words including all eight Persian plosives (/p/, /t/, /k/, /c/, /b/, /d/, /g/, /Ɉ/) in combination with the vowel /æ/. All syllables were recorded in a nearly sound-proof room using PRAAT Software. Independent samples t-test was used to compare the groups across gender. The results revealed: (a) HI children had higher VOT and F0 of onset values in nearly all aspects except for VOT and F0 onset of voiced plosives and F0 onset of alveolar and velar plosives; (b) both groups of girls had higher VOT values than boys did; (c) VOT is affected by the place of articulation and F0 is related to voiced-voiceless classification of plosives. Overall, NH children were able to distinguish and produce sounds more correctly, implying that HI children need further training. The study has implications for speech therapists, clinical linguists, and application designers to focus on speech sounds which are challenging for HI children to produce.