Current Studies

​​​​A Developmental Framework for Linking Phonological and Morpho-syntactic Sequential Pattern Rules in Developmental Language Disorder

Principal Investigators: Lisa Goffman and LouAnn Gerken (University of Arizona)
Funding: NIH, National Institute on Deafness and Other Communication Disorders

A hallmark of English-learning children with developmental language disorder (DLD) is the inconsistent production of grammatical morphology. However, recent work also implicates the phonological domain, as indicated by deficits in nonword repetition and in producing novel word forms. The hypothesis driving the current project is that morphological and phonological deficits are causally linked by a broader deficit in sequential pattern learning. We take a developmental approach, combining what we already know about morphosyntactic deficits in DLD with recent developments in the fields of linguistics and language acquisition. First, it is possible to divide phonological and morphological patterns into three pattern types (Single Feature, OR/Disjunction, Family Resemblance/Prototype), with these types having a long history of study in visual pattern learning. Importantly, children with DLD appear to have maximum difficulty with morpho-syntactic patterns of the OR type (e.g., regular past tense). In contrast, studies using artificial grammars show that infants who are typically developing are highly adept at learning Single Feature and OR pattern types; Family Resemblance patterns may be weaker. Typical adults are adept at Single Feature and Family Resemblance patterns, but appear to be, at least superficially, more like children with DLD in their performance on the disjunctive OR pattern.

The proposed research links deficits in phonological and morphological sequence learning in children with DLD. We also ask if dependence on the associatively organized lexicon can account for the infant-to-adult developmental changes observed for the OR pattern (which is not associatively organized) and thereby explores the possibility that children with DLD rely on their lexicons to compensate for their sequential pattern learning deficit. The results of the proposed studies promise to help identify the underlying mechanism(s) of DLD and to suggest possible intervention strategies, such as employing semantic cues and strengthening lexical organization.

Sequential Pattern Learning in Children with Developmental Language Disorder

Principal Investigator: Lisa Goffman
Funding: NIH, National Institute on Deafness and Other Communication Disorders

Language deficits feature prominently in children diagnosed with DLD, yet there are other cognitive and motor capacities affected—such as pattern induction, rhythmic grouping, and sequential organization. Sequential patterning is a central component of phonology and morphosyntax–domains of language difficulty presented in children with DLD. It has become apparent that this broad profile of deficits cannot be explained by a general motor co-morbidity, but rather forms a core component of DLD. The broad aim of this project is to determine whether learning and generalization would be facilitated by the inclusion of these more basic cognitive operations. Indeed, an exclusive focus on language (especially morphosyntactic) factors in intervention has resulted in slow and laborious learning in children with DLD with only small gains observed.

The central aim of this project is to implement a novel framework for applying domain general cognitive mechanisms to learning and generalization; specifically, all of the proposed experiments have in common the hypothesis that children with DLD will learn more effectively and generalize more broadly when targets are selected to emphasize the regularity of sequential patterns. The outcome of this work has the potential to inform early identification of very young children–when sequence learning (but not grammatical) deficits may be identified–and to alter the substance of intervention to incorporate broad cognitive, language, and motor mechanisms that underlie DLD.