VOWEL AND DIPHTHONG PRODUCTION BY YOUNG USERS OF COCHLEAR IMPLANTS AND THE RELATIONSHIP BETWEEN THE PHONETIC LEVEL EVALUATION AND SPONTANEOUS SPEECH

This investigation assessed how the vowel and diphthong production of young users of cochlear implants varied over time and how performance on the Phonetic Level Evaluation (PLE, Ling, 1976) corresponded with v owel and diphthong production during spontaneous speech. Eight childre n with prelingual deafness were tested with the PLE on five occasions: before receiving a Cochlear Corporation Nucleus cochlear implant and at the following points after receiving a cochlear implant: 6 months, 12 months, 18 months, and 24 or 36 months. An audiovideo recording of spontaneous speech was obtained at each test session. Performance on t he PLE was scored with the scoring system designed by Kirk and Hill-Br own (1985). Performance during spontaneous speaking was scored by refe rencing a transcription of the spoken message to a transcription of th e signed message. The correlations between the PLE and the spontaneous speech measures were weak, suggesting that performance on the PLE has low predictive value for vowel and diphthong production during sponta neous speaking. The results from the spontaneous speech samples collec ted over time suggest that two changes occurred: (a) vowel and diphtho ng production became more diverse and (b) production became more accur ate. It is suggested that increased access to formant information enab les subjects to enlarge their system of phonological performance and r efine their motoric ability to establish vowel and diphthong targets.