The acquisition of English sibilant fricatives by children with bilateral cochlear implants

The English sibilant fricatives /s/ and /ʃ/ are acquired late by normal hearing (NH) children, and pediatric cochlear implant (CI) users lag even further behind their NH peers. Previous work on the acquisition of sibilant fricatives by children with CIs has focused on their performance relative to NH controls, but the developmental trajectory of their sibilant frica- tive acquisition has not been investigated explicitly.
Productions of /s/ and /ʃ/ by children with bilateral CIs were analyzed with Dirichlet regression models in order to determine how their hearing experience and vocabulary development predict their accuracy and error patterns. Hearing age (i.e., total duration of CI use) best predicted the acquisitional trajectories. Neither age at implantation nor chronological age significantly improved the model fit, although receptive vocabulary score did.