Acoustic characteristics of vowels produced by Greek intelligible speakers with profound hearing impairment II: The influence of stress and context.

Purpose: The present paper examines the influence of stress and context on selected acoustic characteristics of vowels produced by six adult Greek intelligible speakers with profound hearing impairment and six speakers with normal hearing (three males and three females in each group).
Method: F1, F2 and F3 formant frequencies and the duration of vowels are measured in words of the form /(')pVCV/ with V = /i, ɛ, ɐ, ɔ, u/ and C = /p, t, k, s/. Variation in these parameters due to context and stress is reported for the two genders. A co-articulatory measure and three measures that examine the area of the vowel space and differences along the F1 and F2 axes are calculated.
Result: The results show a reduction of the vowel space in the unstressed condition for both groups, while vowel duration was found to be significantly longer in this condition for the speakers with hearing impairment. In addition, smaller C-to-V carryover co-articulatory effects were found for the speakers with hearing impairment.
Conclusion: Findings are discussed within the framework of perceptual and production constraints in hearing impairment and with reference to current models of co-articulation.