This study investigates the effects of speaking condition and auditory feedback on vowel production by postlingually deafened adults. Thirteen cochlear implant users produced repetitions of nine American English vowels prior to implantation, and at one month and one year after implantation. There were three speaking conditions (clear, normal, and fast), and two feedback conditions after implantation (implant processor turned on and off). Ten normal-hearing controls were also recorded once. Vowel contrasts in the formant space (expressed in mels) were larger in the clear than in the fast condition, both for controls and for implant users at all three time samples. Implant users also produced differences in duration between clear and fast conditions that were in the range of those obtained from the controls. In agreement with prior work, the implant users had contrast values lower than did the controls. The implant users' contrasts were larger with hearing on than off and improved from one month to one year postimplant. Because the controls and implant users responded similarly to a change in speaking condition, it is inferred that auditory feedback, although demonstrably important for maintaining normative values of vowel contrasts, is not needed to maintain the distinctiveness of those contrasts in different speaking conditions.


The following article appeared in J. Acoust. Soc. Am. Volume 121, Issue 6, pp. 3790-3801 (June 2007) and may be found at http://dx.doi.org/10.1121/1.2710963


hearing aids, speaking condition, auditory feedback

Subject Categories

Hearing, Speech, Postlingual deafness, Cochlear implants


Psychology | Speech and Hearing Science


Acoustical Society of America

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©2007 Acoustical Society of America

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