Acoustic characteristics of Arabic pharyngealized obstruents in children with cochlear implants

Abstract

Speech production of children with cochlear implants (CIs) is generally characterized by low intelligibility and reduced phoneme accuracy. However, limited research investigated their speech production using acoustic measures. The current study examined voice onset time (VOT) for pharyngealized plosives [t,d], and spectral moments and noise duration for pharyngealized fricatives [s,ð] produced by Arabic speaking children with CIs. Productions from children with CIs were compared with both chronological age-matched and hearing experience-matched normal hearing children. Results showed that children with CIs exhibited difficulty producing distinct VOTs between plosives and produced different spectral patterns of both fricatives relative to both comparison groups; however, they were able to produce an acoustic distinction between both fricatives. Children with CIs produced the fricatives with lower spectral mean and higher skewness and kurtosis. The sources for inter-group differences in the acoustic measures appeared to be due in part to limitations in the quality of auditory input provided by CIs as well as reduced motor experience in speech production. Results suggest that VOT and spectral moments are sensitive to changes in perceived sound quality. Spectral moments analysis appears to give details on subtle aspects of fricative production at the phonetic level beyond that available using perceptual judgments.