Children with SLI exhibit delays resolving ambiguous reference

What Children with Developmental Language Disorder Teach Us About Cross-Situational Word Learning

Children with developmental language disorder (DLD) served as a test case for determining the role of extant vocabulary knowledge, endogenous attention, and phonological working memory abilities in cross‐situational word learning. First‐graders (M_age = 7 years; 3 months), 44 with typical development (TD) and 28 with DLD, completed a cross‐situational word‐learning task comprised six cycles, followed by retention tests and independent assessments of attention, memory, and vocabulary. Children with DLD scored lower than those with TD on all measures of learning and retention, a performance gap that emerged in the first cycle of the cross‐situational protocol and that we attribute to weaknesses in initial encoding. Over cycles, children with DLD learned words at a similar rate as their TD peers but they were less flexible in their strategy use, demonstrating a propose‐but‐verify approach but never a statistical aggregation approach. Also, they drew upon different mechanisms to support their learning. Attention played a greater role for the children with DLD, whereas extant vocabulary size played a greater role for the children with TD. Children navigate the problem space of cross‐situational learning via varied routes. This conclusion is offered as motivation for theorists to capture all learners, not just the most typical ones.

Diagnosis of Developmental Language Disorder in Research Studies

Purpose The aim of this study was to investigate the extent to which researchers in the field of developmental language disorder are utilizing validated methods to diagnose their research participants. Method We examined 90 research articles published from 2015 to 2019 that included English-speaking participants from the United States who were identified as having a developmental language disorder or specific language impairment. From these articles, we identified the tests and measures used to identify participants and classify them as healthy or impaired. We then consulted the test manuals and the literature to find information on sensitivity and specificity of the test and the evidence-based cut score that maximized identification accuracy. Results Of the 90 articles examined, 38 (42%) were found to reflect validated diagnostic methods, and 51 (58%) did not. Conclusion Our results illustrate that validated methods are used less than half of the time even by those who should have a high level of expertise and despite calls for increasing scientific rigor in research practices.

The Relationship Between Word Learning and Executive Function in Preschoolers With and Without Developmental Language Disorder

Purpose The purpose of this study was to examine the relationship between executive functioning and word learning among preschoolers with and without developmental language disorder (DLD). Method Forty-one preschool-age children with DLD were matched to typically developing children on age and sex. Participants were exposed to 10 novel pseudowords, half of which referred to familiar objects and half of which referred to unfamiliar objects. Their ability to produce, recognize, and comprehend the novel words was tested, and they completed executive function tasks measuring sustained selective attention, short-term memory, working memory, inhibition, and shifting. Results Preschoolers with DLD performed worse compared to typically developing peers on all measures of executive function and novel word learning. Both groups showed a relative weakness in producing pseudowords that corresponded with familiar objects versus pseudowords for unknown objects. Executive function accounted for statistically significant variance in word learning beyond group membership, with inhibition as a significant predictor of all word learning outcomes and short-term memory as a significant predictor of novel word comprehension. Executive function explained significant variance in novel word production and recognition even after accounting for variance explained by group differences in IQ and receptive vocabulary. Conclusion Findings replicate previous research reporting deficits in word learning and executive function in children with DLD, indicate that preschoolers are disadvantaged in learning new words for familiar objects, and support a relationship between executive function and word learning for children with and without DLD. Future research should examine the directionality of the relationship between these variables.

The role of developmental change and linguistic experience in the mutual exclusivity effect

Given a novel word and a familiar and a novel referent, children have a bias to assume the novel word refers to the novel referent. This bias - often referred to as "Mutual Exclusivity" (ME) - is thought to be a potentially powerful route through which children might learn new word meanings, and, consequently, has been the focus of a large amount of empirical study and theorizing. Here, we focus on two aspects of the bias that have received relatively little attention in the literature: Development and experience. A successful theory of ME will need to provide an account for why the strength of the effect changes with the age of the child. We provide a quantitative description of the change in the strength of the bias across development, and investigate the role that linguistic experience plays in this developmental change. We first summarize the current body of empirical findings via a meta-analysis, and then present two experiments that examine the relationship between a child's amount of linguistic experience and the strength of the ME bias. We conclude that the strength of the bias varies dramatically across development and that linguistic experience is likely one causal factor contributing to this change. In the General Discussion, we describe how existing theories of ME can account for our findings, and highlight the value of computational modeling for future theorizing.