Language development in rural and urban Russian-speaking children with and without developmental language disorder

Testing the Continuum/Spectrum Model in Russian-Speaking Children With and Without Developmental Language Disorder

PURPOSE

Previously, Lancaster and Camarata (2019) showed that the continuum/spectrum model of the developmental language disorder (DLD) best explained the high heterogeneity of symptoms in children with DLD. We hypothesize that the continuum/spectrum approach can include not only children with DLD but also typically developing (TD) children with different timelines and patterns of language acquisition. This model can explain individual language profiles and deficits in children.

METHOD

We assessed language abilities in a group of Russian-speaking children with DLD aged 4-7 years (n = 53) and their age- and gender-matched peers without speech and language diagnoses (n = 53, TD). We evaluated the children's performance at four language levels in production and comprehension domains, using 11 subtests of the standardized language assessment for Russian: Russian Child Language Assessment Battery (RuCLAB). Using the k-means cluster method and RuCLAB scores, we obtained two clusters of children and analyzed their language performance in individual subtests.

RESULTS

The analysis revealed that the two clusters of children both included DLD and TD participants: Group 1, with higher test scores (TD = 45, DLD = 24 children), and Group 2, with lower scores (TD = 8, DLD = 29). Children from Group 1 mostly had lower scores at one of the language levels, whereas those from Group 2 struggled at several language levels. Furthermore, children with DLD from both groups tended to be more sensitive to linguistic features such as word length, noun case, and sentence reversibility compared to TD children.

CONCLUSIONS

The presence of two mixed groups shows that children with diagnosed DLD could perform on par with TD children, whereas some younger TD children could perform similarly to children with DLD. Our findings support the continuum/spectrum model: Linguistic skills in preschool children are a continuum, varying from high to poor skills at all language levels in comprehension and production. To describe a child's language profile, the tasks assessing all language levels should be used.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25521400.

Probabilistic causal reasoning under time pressure

While causal reasoning is a core facet of our cognitive abilities, its time-course has not received proper attention. As the duration of reasoning might prove crucial in understanding the underlying cognitive processes, we asked participants in two experiments to make probabilistic causal inferences while manipulating time pressure. We found that participants are less accurate under time pressure, a speed-accuracy-tradeoff, and that they respond more conservatively. Surprisingly, two other persistent reasoning errors-Markov violations and failures to explain away-appeared insensitive to time pressure. These observations seem related to confidence: Conservative inferences were associated with low confidence, whereas Markov violations and failures to explain were not. These findings challenge existing theories that predict an association between time pressure and all causal reasoning errors including conservatism. Our findings suggest that these errors should not be attributed to a single cognitive mechanism and emphasize that causal judgements are the result of multiple processes.

Measurement of expressive vocabulary in school-age children: Development and application of the Kilifi Naming Test (KNT)

The dearth of locally developed measures of language makes it difficult to detect language and communication problems among school-age children in sub-Saharan African settings. We sought to describe variability in vocabulary acquisition as an important element of global cognitive functioning. Our primary aims were to establish the psychometric properties of an expressive vocabulary measure, examine sources of variability, and investigate the measure's associations with non-verbal reasoning and educational achievement. The study included 308 boys and girls living in a predominantly rural district in Kenya. The developed measure, the Kilifi Naming Test (KNT), had excellent reliability and acceptable convergent validity. However, concurrent validity was not adequately demonstrated. In the final regression model, significant effects of schooling and area of residence were recorded. Contextual factors should be taken into account in the interpretation of test scores. There is need for future studies to explore the concurrent validity of the KNT further.