목적: The purpose of this study is to investigate the vocal development in toddlers with simultaneous bilateral cochlear implants (bilateral CI group) and to compare their progress to that of chronological age- matched (CA group) and hearing age-matched (HA group) who have normal hearing and typical development. 방법:Thirteen toddlers who received bilateral CIs simultaneously before 13 months of age participated in this study. 26 toddlers participated as the control groups (CA and HA groups). The spontaneous utterances were collected from each toddler during free play with their parents in the laboratory. Spontaneous utterances of 39 toddlers were classified as either canonical vocalizations or noncanonical vocalizations. 결과:The bilateral CI group produced significantly fewer canonical vocalizations than the CA group. However, there was not a significant difference in the ratio of canonical vocalizations between the CI and the CA groups. There were no significant differences in the frequency and ratio of canonical vocalization between the CI and HA groups. In the CI group, the frequency of canonical and noncanonical vocalizations was significantly correlated with receptive and expressive language scores. 결론:The findings of this study showed that toddlers with bilateral CIs make good advancements in vocal development compared to toddlers with normal hearing. However, toddlers with bilateral CIs seem to produce insufficient canonical vocalizations compared to age-matched hearing toddlers. The quantity of vocalizations was related to language development in toddlers with bilateral CIs. Information about vocal development following simultaneous bilateral CI helps speech therapists and parents recognize the speech and language development of toddlers with bilateral CIs before using intelligible speech in communication.