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.

Keywords:

• Acoustics
• adults
• hearing impairment

Acknowledgements

Thanks are due to all the participants of the study, to Giorgos Vlahavas and Kostas Dimopoulos for assistance in statistical processing and mathematical calculations, and to Tasos Pasxalis for technical assistance.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Notes

* When the experiment of the study was conducted, Aristotle University had not yet established an Institutional Review Board and, therefore, permission to conduct the study could not be requested.

* Between-group differences in F1 and/or F2 frequencies varied for the five vowels. Figures 2(a) and (b), for example, illustrate this by showing that there is a large difference in the F2 of /i/ between the two groups but not of // both for male and female speakers.