[en] The contribution of the cochlear implant (CI) to language development is undeniable: implanted deaf children are able to acquire high linguistic skills and intelligible speech over a period of time quite similar to that of normal-hearing children, with as favorable factors the precocity of implantation and binaurality [1,2]. Despite these advances, in comparison with normal-hearing children, deaf children with CI still exhibit some persistent language difficulties in relation with morphosyntax and suprasegmentals (such as prosody or speech rate [3]). Phonetic/phonological levels also have interesting idiosyncrasies in children with CI, while the lexical level seems more or less preserved. It is sensible to assume that the persistence of atypicalities is due to the fact that children with CI develop their speech and language production and perception skills under limited sensory capabilities, the input acoustic bandwidth being reduced and exploited through a small number of transmission channels.
In this paper, we will first present the results of an exploratory study based on the acoustic and perceptual analysis of spontaneous language samples of young children with CI (4 recordings). In several instances, the speech productions of these children show pervasive hypo- or hyper-nasality, suggesting that phonetic nasality is poorly perceived (and contrastive phonological nasalization later acquired) in children with CI. Moreover, we observe atypical prosodic patterns, seemingly organized around lexical and nominal phrases. We hypothesize that this particular suprasegmental structuring, together with difficulties in perceiving phonetic cues such as nasality, could lead to atypical morphosyntactical development (note that several grammatical morphemes are coded through phonological nasalization in French: paysan-paysanne; mangera-mangeront). In a second step, we will describe a collaborative research project between universities (UMONS, ULB) and the 'Comprendre & Parler' center for intervention, which aim is to carry out a large-scale longitudinal study of language development in children with CI. During the presentation, we will discuss preliminary results (on data currently being acquired) concerning: (i) the categorical perception and the production of voiced vs. voiceless stops, and (ii) the discrimination between (and production of) oral vs. nasal vowels in normal-hearing and implanted francophone children aged 5 to 10.
