Acoustic characteristics of vowels produced by Greek intelligible speakers with profound hearing impairment I: Examination of vowel space

Abstract

Purpose: The study examines F1, F2 and F3 formant frequencies of vowels produced by six Greek intelligible speakers with profound hearing impairment and six speakers with normal hearing (three male and three female in each group).Method: The formant frequencies are measured in words of the form /ʹpVCV/ where V = /i, , , , u/ and C = /p, t, k, s/. The study examines differences in formant frequencies between the two groups and as a function of gender. Three measures are calculated to examine the area of the vowel space and differences along the F1 and F2 axes between the groups and genders.Result: The results show that the vowel space produced by the speakers with hearing impairment is considerably reduced. Greater reduction was evident for F2 compared to F1. Restricted formant frequency ranges and relatively large variation along F1 and/or F2 for selected vowels resulted in overlap among vowel categories. F3 frequencies were systematically lower and showed greater variation for the speakers with hearing impairment.Conclusion: The paper discusses findings with reference to perceptual and production constraints affecting the speech of individuals with hearing impairment.