Statistical word learning in Catalan-Spanish and English-speaking children with and without developmental language disorder

Abstract

A growing body of work shows that children with developmental language disorder (DLD) perform poorly on statistical word learning (SWL) tasks, consistent with the predictions of the Procedural Deficit Hypothesis that predicts that procedural memory is impaired in DLD. To date, however, SWL performance has not been compared across linguistically heterogeneous populations of children with DLD. Aims: To compare SWL performance in a group of age, sex and non-verbal IQ-matched Catalan-Spanish and English-speaking children with and without DLD. Methods & Procedures. Two cohorts of children: (1) 35 Catalan-Spanish-speaking children with DLD (Mage = 8;7 years) and 35 age/sex-matched typical developing (TD) children (Mage = 8;9 years), and (2) 24 English-speaking children with DLD (Mage = 9;1 years) and 19 age/sex matched TD controls (Mage = 8;9 years) completed the tone version of a SWL task from Evans et al. (2009). Children listened to a tone language in which transitional probabilities within tone words were higher than those between words. Outcomes & Results. For both Catalan-Spanish and English cohorts, overall performance for the children with DLD was poorer than that of the TD controls regardless of the child's native language. Item analysis revealed that children with DLD had difficulty tracking statistical information and using transitional probability to discover tone word boundaries within the input. For both the Catalan-Spanish and English-speaking children, SWL accounted for a significant amount of unique variance in Receptive and Expressive vocabulary. Likelihood ratio analysis revealed that for both Catalan-Spanish and English cohorts, children having performance - 45% on the SWL task had an extremely high degree of likelihood of having DLD. The analysis also revealed that for the Catalan-Spanish and English-speaking children, scores of > 75% and > 70%, respectively, were highly likelihood to be children with normal language abilities. Conclusions & Implications. The findings add to a pattern suggesting that SWL is a mechanism that children rely on to acquire vocabulary. The results also suggest that SWL deficits, in particular when combined with other measures, may be a reliable diagnostic indicator for children with DLD regardless of the child's native language, and whether or not the child is bilingual or monolingual.