Abstract: Objective To observe the pronunciation characteristics of vowels' tone in prelingual hearing-impaired children accepted cochlear implant (CI). Methods 8 prelingual hearing-impaired children accepted CI aged 3~4 years (group CI) and 8 normal-hearing children (group NH) with the same age were asked to pronounce the vowels of /a/, /o/, /e/, /i/, /u/, and /ü/ in four tones with the direction of speech training teacher. The sounds were recorded and analyzed with Praat software extract Formants (F1, F2) and duration of the sounds. Results The error of vowels in four tones was more in group CI than in group NH, but difficult level was almost the same between groups. There was significant difference in the F1 of /e/, F2 of /i/ and /u/ in tone 2, F2 of /e/ and duration of /o/, /e/, and /ü/ in tone 3 between groups (P<0.05). Conclusion Pronouncing the four tones of vowels is more difficult for the hearing-impaired children. For vowels articulation training,it is important to focus on the mouth and breath training.

Key words: cochlear implant, acoustic analysis, tones, vowels