Bilingual speech production and intelligibility of a post-lingually deaf adult, pre-/post-cochlear implantation.

摘要

This study investigates changes in speech production for a multilingual adult male who is postlingually deaf (9 years of hearing) following cochlear implantation (CI). He simultaneously acquired Twi (dominant language) and Fante in the home and British-English in the community before the onset of deafness. Recordings of words in carrier phrases took place at pre-implantation in English, 2 months post-implantation for Twi, and at 6 months, 1 year, 1 year 6 months, and 2 years post-implantation in both languages. Normative data were recorded from a typically-hearing adult male with a similar linguistic history. Acoustic measurements for English included fundamental frequency (f0), first and second formants of vowels (F1 and F2), stop consonant voicing, and voice quality for sustained /a/. Acoustic measurements for Twi included F1 and F2 of vowels that undergo vowel harmony and f0 of tonal words embedded. Information about CI usage and self-reported changes in production/perception were obtained, as were forced-choice speech intelligibility ratings of English words from inexperienced monolingual English listeners. Results suggest greater preservation of Twi than English and improved segmental and suprasegmental parameters over time, particularly for English. Intelligibility ratings were largely consistent with acoustic measures. These data contribute to the limited research available on speech production of individuals who are multilingual CI users.