Synthesis of sign and speech in a New Zealand Sign Language-target session: Oral channel variation of hearing bimodal bilingual children of Deaf parents

This thesis investigates the uniquely “bimodal” bilingual language production of some of the New Zealand Deaf community’s youngest members—hearing and cochlear-implanted Deaf children who have Deaf signing parents. These bimodal bilinguals (aged 4-9 years old) are native users of two typologically different languages (New Zealand Sign Language (NZSL) and English), and two modalities (visual-manual and auditory-oral). The primary focus of this study is the variation found in the oral channel produced by these bimodal bilingual children, during a sign-target session (i.e. a signed conversation with a Deaf interlocutor), involving a game designed to elicit location and motion descriptions alongside a sociolinguistic interview. The findings of this study are three-fold. Firstly, the variation of audible and visual volumes of the oral channel (the spoken modality) between and within participants’ language sessions is described. Notably, audible volume ranges from voiceless, whispered, and fully-voiced productions. Audible volume is found to have an inverse relationship with visual volume, in that reduced auditory cues reflect an increase in visual cues used for clarification. Additionally, a lowered audible volume (whispers or voiceless mouthings) is associated with reduced English, aligning with some NZSL grammatical structures, while full-voice is associated with intact English grammatical structures. Transfer in the opposite direction is also evident during descriptions of a motion event, in that English structures for encoding ‘path’ surface in the manual channel (the signed modality). Bidirectional transfer also occurs simultaneously, where structures of both languages surface in both linguistic channels. Secondly, the coordination of the oral and manual channels during descriptions of location and motion is described. Notably, the linguistic channels are tightly temporally synchronised in the coordination of meaning. The oral channel can function gesturally by modifying or emphasising meaning in the manual channel; a similar function to co-speech gesture used by hearing users of spoken languages. Thirdly, this thesis details the children’s attitudes towards their use of NZSL and English, highlighting their sensitivity to the uniqueness of their heritage language, the movement between Deaf and hearing worlds and associated languages, and their role in passing on their sign language to other hearing people. Their Deaf/Coda and hearing cultural identification is found to be entangled in use of both oral and manual channels. The oral channel is multifaceted in the ways it functions for both the bimodal bilingual child and their Deaf interlocutor, and thus operates at the intersection of language, cognition and culture. Bimodal bilinguals’ use of the oral channel is influenced by the contact situation that exists between Deaf and hearing communities, the cognitive cost of language suppression, and the interactional setting. This study contributes to growing global research conducted on the language production of bimodal bilinguals. It provides preliminary insight into oral channel features of young native NZSL users as a way of better understanding bimodal bilingual language development, the connections between audiological status and language, the interplay of codes across linguistic channels, and the role that modality plays in shaping meaning across all human languages.