Words and non-words : Vocabulary and phonological working memory in Arabic-Swedish-speaking 4–7-year-olds with and without a diagnosis of Developmental Language Disorder

Abstract: This thesis investigates the vocabulary skills and the non-word repetition (NWR) performance of 99 typically developing (TD) 4­­–7-year-old Arabic-Swedish-speaking children and 11 Arabic-Swedish-speaking children with a diagnosis of Developmental Language Disorder (DLD). The children’s early language development, family backgrounds and language exposure patterns are explored through parental questionnaires, and for the DLD children also via interviews with parents, teachers and speech-language pathologists regarding their developmental history, language skills and communicative behaviour. Vocabulary comprehension and production is assessed with Cross-linguistic Lexical Tasks (CLT; Haman et al. 2015) in Arabic and Swedish. Phonological working memory is assessed with four different NWR tasks with varying item length, phonological complexity and language-likeness (Radeborg et al. 2006, Chiat 2015, Abou Melhem et al. 2011). For vocabulary, differences between the two languages (Arabic and Swedish) and differences between comprehension and production are explored, as well as effects of age, exposure and socioeconomic status (SES). For NWR, effects of age, task, item length and phonological complexity are investigated, as well as effects of vocabulary and exposure.Results: Vocabulary comprehension and production scores were found to increase with age in both Arabic and Swedish. Daily language exposure predicted comprehension and production scores in Arabic, but only production scores in Swedish. Length of exposure to Swedish was the most important predictor of Swedish vocabulary scores. SES (parental education) did not predict vocabulary scores in either language. For NWR, scores increased with age on all tasks. There were also task and item effects. Factors related to NWR performance were type of task, item length, phonological complexity and vocabulary skills.At group level, the DLD children scored below their TD peers on both vocabulary and NWR tasks. Many DLD children had particularly low vocabulary scores in their first language (Arabic), despite extensive and continuous exposure from birth. There was substantial overlap between the TD and the DLD groups on NWR performance, and not all DLD children scored low on NWR. Having a history of language delay or language difficulties in the family was more common among the DLD children than the TD children. The study underscores the importance of considering patterns of language exposure and developmental history when assessing the language skills of bilingual children with potential DLD.