Can verbal working memory and processing speed distinguish between children who have English as an additional language and children with developmental language disorder?

Abstract

Background: Children with English as an Additional Language (EAL) often present with language difficulties and make errors that are similar to children with Developmental Language Disorder (DLD). Apparent language difficulties, which may be attributed to a child’s EAL status, are instead misunderstood as being a Developmental Language Disorder (DLD) (Raul & Ahyea, 2017). Research illustrates how assessment tools are often biased against children with EAL (Alfano, Holden & Conway, 2016). Following a systematic review of the literature, a corpus of evidence suggested that less-biased assessments, such as tests of Verbal Working Memory (VWM) and Processing Speed can distinguish children with EAL from children with DLD (Sandgren & Holmström, 2015).

Aim: The aim of the research was to ascertain if tests of VWM and Processing Speed could distinguish between children with EAL and children who had a DLD.

Method: Participants from monolingual (n = 15), EAL (n = 15) and DLD (n = 12) groups, who were aged between seven and nine years old, completed literacy and intelligence screening, followed by a Visual Search and Nonword Repetition Test (NRT). completed literacy and intelligence screening, followed by a Visual Search and Nonword Repetition Test (NRT). The latter two tests measured Processing Speed and VWM, respectively.

Results: Influenced by a post-positivist stance, results have indicated that the NRT (i.e., VWM) can distinguish between children who have EAL and children who have a DLD, p < .001, η² = .457 (i.e., medium effect, Cohen, 1988). The DLD group also scored lower on the Visual Search task but this did not reach the significance level. Likelihood ratios and tests of specificity and sensitivity using a Receiver Operating Characteristic (ROC) Curve also indicated that the VWM measure had a good degree of accuracy.

Conclusion: Assessments of VWM using non-words may be able to differentiate between children who have EAL and children who have DLD. Such findings could hold implications for educational psychology practice, research and policy, nationally and internationally.