A total of 1,018 signs in one deaf child's naturalistic interaction with her deaf mother, between the ages of 19 and 24 months were analyzed. This study summarizes regular modification processes in the phonology of the child sign's handshape, location, movement, and prosody. First, changes to signs were explained by the notion of phonological markedness. Second, the child managed her production of first signs through two universal processes: structural change and substitution. Constraints unique to the visual modality also caused sign language-specific acquisition patterns, namely, more errors for handshape articulation in locations in peripheral vision, a high frequency of whole sign repetitions and feature group rather than one-to-one phoneme substitutions as in spoken language development.

Recent studies suggest that deaf children perform more poorly on working memory tasks compared to hearing children, but do not say whether this poorer performance arises directly from deafness itself or from deaf children’s reduced language exposure. The issue remains unresolved because findings come from (1) tasks that are verbal as opposed to non-verbal, and (2) involve deaf children who use spoken communication and therefore may have experienced impoverished input and delayed language acquisition. This is in contrast to deaf children who have been exposed to a sign language since birth from Deaf parents (and who therefore have native language-learning opportunities). A more direct test of how the type and quality of language exposure impacts working memory is to use measures of non-verbal working memory (NVWM) and to compare hearing children with two groups of deaf signing children: those who have had native exposure to a sign language, and those who have experienced delayed acquisition compared to their native-signing peers. In this study we investigated the relationship between NVWM and language in three groups aged 6-11 years: hearing children (n=27), deaf native users of British Sign Language (BSL; n=7), and deaf children non native signers (n=19). We administered a battery of non-verbal reasoning, NVWM, and language tasks. We examined whether the groups differed on NVWM scores, and if language tasks predicted scores on NVWM tasks. For the two NVWM tasks, the non-native signers performed less accurately than the native signer and hearing groups (who did not differ from one another). Multiple regression analysis revealed that the vocabulary measure predicted scores on NVWM tasks. Our results suggest that whatever the language modality – spoken or signed – rich language experience from birth, and the good language skills that result from this early age of aacquisition, play a critical role in the development of NVWM and in performance on NVWM tasks.

Research into the effect of phonetic complexity on phonological acquisition has a long history in spoken languages. This paper considers the effect of phonetics on phonological development in a signed language. We report on an experiment in which nonword-repetition methodology was adapted so as to examine in a systematic way how phonetic complexity in two phonological parameters of signed languages — handshape and movement — affects the perception and articulation of signs. Ninety-one Deaf children aged 3–11 acquiring British Sign Language (BSL) and 46 hearing nonsigners aged 6–11 repeated a set of 40 nonsense signs. For Deaf children, repetition accuracy improved with age, correlated with wider BSL abilities, and was lowest for signs that were phonetically complex. Repetition accuracy was correlated with fine motor skills for the youngest children. Despite their lower repetition accuracy, the hearing group were similarly affected by phonetic complexity, suggesting that common visual and motoric factors are at play when processing linguistic information in the visuo-gestural modality.