Objective-To compare how children who use either cochlear implants (CIs) or hearing aids (HAs) express English inflectional morphemes during conversation, i.e., with voice, with sign, or with both. A secondary objective was to investigate the relationship between morpheme use in pediatric CI users and their speech perception skills, length of experience with the device, and accuracy of phoneme production.Design-Group 1 consisted of 25 children who used CIs, and Group 2 consisted of 13 children who used HAs. All children were prelingually deafened and all used simultaneous communication. A 12 minute spontaneous conversation was elicited, transcribed and coded. Between group comparisons were performed to evaluate differences in modality and number of morphemes used. Additionally, use of morpheme endings was related to length of CI experience, accuracy of phoneme production, and closed-set speech recognition performance.Results-Children who had CI experience produced significantly more English inflected morphemes than children in the HA group. CI participants also expressed the inflected endings by using voice-only mode 91% of the time, whereas HA participants used voice-only mode 1% of the time. In the CI group, a strong relationship was found between number of morpheme endings used and speech recognition scores, length of CI experience and accuracy of phoneme production. The results of this study indicate that input from the CI facilitates children's ability to perceive and comprehend bound morphemes.This investigation focused on the use of English inflectional morphology by young cochlear implant (CI) users who communicate primarily with Signed English. Our goal was to evaluate the acquisition of inflectional endings, and to explore the role of CI use in their development. The first section of the following review indicates that little research exists concerning the language skills of young CI users. In the next sections, we note that these children often acquire the speech skills necessary to produce the sounds associated with plurals and third person possessive, /s, z/, past tense /t, d/, as well as the /m/ associated with first person possessive (i.e., I'm), and the /ng/ associated with the present progressive tense. As will be noted, CI children can often hear these sounds, so they may receive exposure to them during everyday listening. Robbins, Osberger, Miyamoto, & Kessler, 1995).Improvements in receptive and expressive vocabulary and syntax skills often follow receipt of a CI (Geers & Moog, 1994;Miyamoto, Osberger, Robbins, Myres, Kessler, & Pope, 1992). For instance Miyamoto et al. (1992) reported small improvements in receptive vocabulary in a group of children after they used a CI for 2.5 yr as indexed by quotient scores on the Peabody Picture Vocabulary Test-Revised (Dunn & Dunn, 1981). Geers and Moog (1994) reported that after 3 yr of devise use, children who used CIs performed better than children who used hearing aids (HAs) on the receptive language test, Rhode Island Test of Language Stru...