Phonological characteristics of novel gesture production in children with developmental language disorder: Longitudinal findings

A developmental account of the role of sequential dependencies in typical and atypical language learners

The Gerken lab has shown that infants are able to learn sound patterns that obligate local sequential dependencies that are no longer readily accessible to adults. The Goffman lab has shown that children with developmental language disorder (DLD) exhibit deficits in learning sequential dependencies that influence the acquisition of words and grammar, as well as other types of domain general sequences. Thus, DLD appears to be an impaired ability to detect and deploy sequential dependencies over multiple domains. We meld these two lines of research to propose a novel account in which sequential dependency learning is required for many phonological and morphosyntactic patterns in natural language and is also central to the language and domain general deficits that are attested in DLD. However, patterns that are not dependent on sequential dependencies but rather on networks of stored forms are learnable by children with DLD as well as by adults.

Phonological and Articulatory Deficits in the Production of Novel Signs in Children With Developmental Language Disorder

PURPOSE

Sign language, like spoken language, incorporates phonological and articulatory (or motor) processing components. Thus, the learning of novel signs, like novel spoken word forms, may be problematic for children with developmental language disorder (DLD). In the present work, we hypothesize that phonological and articulatory deficits in novel sign repetition and learning would differentiate preschool-age children with DLD from their typical peers.

METHOD

Children with DLD (n = 34; aged 4-5 years) and their age-matched typical peers (n = 21) participated. Children were exposed to four novel signs, all iconic, but only two linked to a visual referent. Children imitatively produced these novel signs multiple times. We obtained measures of phonological accuracy and articulatory motion stability as well as of learning of the associated visual referent.

RESULTS

Children with DLD showed an increased number of phonological feature (i.e., handshape, path, and orientation of the hands) errors when compared with their typical peers. While articulatory variability did not overall differentiate children with DLD from typical peers, children with DLD showed instability in one novel sign that obligated bimanual oppositional movement. Semantic aspects of novel sign learning were unaffected in children with DLD.

CONCLUSIONS

Deficits that have been documented in phonological organization of spoken words in children with DLD are also evident in the manual domain. Analyses of hand motion variability suggest that children with DLD do not show a generalized motor deficit, but one that is restricted to the implementation of coordinated and sequential hand motion.