Acoustic Development of Vowel Production by Prelingually Deaf Chinese Mandarin-speaking Children with Cochlear Implants

This study investigated the developmental profiles of vowel production by CI (cochlear-implanted) children, with hearing age (HA) approximately ranging from 2 to 8 years, specially emphasizing on the acoustic properties. The main purpose was to obtain a comprehensive understanding about how CI children acquire Mandarin vowels phonetically as the function of HA. Spectral and temporal measurements were made in all the seven Mandarin monophthongs. The results showed that: 1) with longer device use, CI children could develop better vowel intelligibility by decentralizing and decompressing the surface area of vowel space; 2) CI children were able to produce different vowels acoustically, but even with 8-year device use, they still showed deficits in refining the articulatory gestures, including both the tongue height and tongue retraction; 3) like most NH (normal-hearing) peers, the CI children can accurately manipulate temporal cues to distinguish different vowels with 2 years’ device use.