Acoustics of long vowels in Arabic-speaking children with hearing impairments

The present study investigates formant frequencies and vowel space area in Jordanian hearing-impaired individuals who received cochlear implants. To achieve this task, they were compared with their hearing aids and normal-hearing peers. The study involved 60 participants aged between 7 and 11 years, consisting of 20 cochlear implant (CI) users, 20 hearing aid (HA) users, and 20 normal-hearing (NH) children. All participants were native speakers of Jordanian Arabic. The study measured the fundamental frequency (F0), the first, second, and third formant frequencies (F1-F3) of the five long vowels: /i:/, /e:/, /a:/, /o:/, and /u:/ using Praat software (version 6.1.05). One-way repeated measure (ANOVA) and post hoc Tukey tests were used to compare the differences between the three groups. The results revealed significant differences between the three groups in the degree of vowel height and backness for all the long vowels. The vowel space in HA users was found to be smaller than in CI users. HA users had difficulty varying their tongue position in both the high-low and the front-back dimensions, while CI users had difficulty varying their tongue position only in the front-back dimension. The study also examined errors in long vowels and diphthongs. The findings indicated that after cochlear implantation, the formants of the vowels produced by hearing-impaired speakers shifted closer to those produced by their NH peers, and CI users had a greater vowel space compared to HA users. This research could potentially contribute to the development of effective interventions for hearing-impaired individuals and could provide insights for the design of speech therapy programs that aim to improve vowel production abilities.