Clinical markers of developmental language disorder in Arabic

Data on the typical and impaired acquisition of Arabic is limited and only a few standardized Arabic language assessments are available. As a result, the identification of developmental language disorder (DLD) in Arabic is notoriously challenging. Developing new diagnostic language tools is thus imperative to facilitate early and accurate identification of DLD in Arabic-speaking children with a view to developing relevant interventions. This thesis addressed this issue by investigating potential clinical markers of DLD in Arabic through three theoretically grounded studies focusing on the linguistic and processing deficits that characterize Arabic speaking children with DLD and could be used as indicators of the presence of the disorder. Study 1 showed that the production of verb tense and subject-verb agreement is generally impaired in 5-year-old Arabic-speaking children with DLD relative to same-age peers. Study 1 showed that poor use of present tense and subject-verb feminine agreement could be potential grammatical markers of DLD in Arabic. Study 2 revealed that nonword repetition is an area of difficulty for 4 to 6-year-old Arabic-speaking children with DLD. Importantly, Study 2 found that poor nonword repetition accurately identified 93% of children with DLD and 93% of age-matched TD children, suggesting that poor nonword repetition could also be a possible clinical marker of DLD in Arabic. Study 3 reported poor sentence repetition abilities in 4 to 6- year-old Arabic-speaking children; the sentence repetition task correctly identified more than 90% of children with DLD and more than 90% of age-matched TD children. Study 3 thus suggests that poor sentence repetition may also hold promise as a potential clinical marker for the presence or absence of DLD in Arabic. The findings of this thesis could help enhance the diagnostic practices of DLD in Arabic-speaking children by focusing clinicians’ attention on relevant tasks which could aid diagnosis. The findings extend our understanding of the underlying mechanisms of DLD. Specifically, the language difficulties of Arabic-speaking children with DLD seem to reflect a combination of deficits in linguistic knowledge and processing capacity. This thesis is the first study to my knowledge to address the issue of clinical markers of DLD in Arabic and as such it paves the way and highlights the need for further research to better characterize the linguistic and non-linguistic, as well as the functional limitations in Arabic-speaking children with DLD

Sentence repetition as a clinical marker of developmental language disorder: evidence from Arabic

Purpose: Research on the typical and impaired grammatical acquisition of Arabic is limited. This study systematically examined the morpho-syntactic abilities of Arabic-speaking children with and without Developmental Language Disorder (DLD) using a novel sentence repetition task. The usefulness of the task as an indicator of DLD in Arabic was determined. Methods: A sentence repetition task was developed in Palestinian Arabic (LITMUS-SR-PA-72) and administered to 30 children with DLD (M = 61.50 months, SD = 11.27) and 60 age-matched TD children (M = 63.85 months, SD = 10.16).The task targeted grammatical structures known to be problematic for Arabic-speaking children with DLD (language-specific) and children with DLD across languages (language-independent). Responses were scored using binary, error and structural scoring methods. Results: Children with DLD scored below TD children on the LITMUS-SR-PA-72 in general as well as in the repetition of language-specific and language-independent structures. The frequency of morpho-syntactic errors was higher in the DLD group relative to the TD group. Despite the large similarity of the type of morpho-syntactic errors between the two groups, there were some atypical errors exclusively produced by the DLD group. The three scoring methods showed good diagnostic power in the discrimination between children with and without DLD. Conclusion: Sentence repetition was an area of difficulty for Palestinian Arabic-speaking children with DLD. The DLD group demonstrated difficulties with language-specific and language-independent structures, particularly complex sentences with non-canonical word order. Most grammatical errors made by the DLD group resembled those of the TD group and were mostly omissions or substitutions of grammatical affixes or omissions of function words. SR appears to hold promise as a good indicator for the presence or absence of DLD in Arabic. Further validation of these findings using population-based studies is warranted

Expressive verb morphology deficits in Arabic-speaking children with Developmental Language Disorder

Purpose This study investigated the production of tense and subject-verb agreement in Palestinian Arabic-speaking children with Developmental Language Disorder (DLD) in comparison to their typically developing peers (TD) in terms of (1) performance accuracy and (2) error patterns. Method Participants were 14 children with DLD aged 4;0 - 7;10 (years; months) and 32 TD children aged 3;0-8;0 (years; months) matched on non-verbal abilities. Children were asked to complete a picture-based verb elicitation task. The task was designed to measure the production accuracy of tense and subject-verb agreement inflections in Arabic. Results The DLD group scored significantly lower than the TD group on the verb elicitation task. The DLD group was significantly less accurate than the TD group in marking tense, specifically present tense. They were also less accurate in marking agreement in general, with specific difficulty in using feminine verb forms. The DLD and TD groups differed in their tense error patterns, but not in agreement error patterns. Conclusion The acquisition of verb morphology in Palestinian Arabic-speaking children with DLD appears to be delayed and possibly different from their TD peers. The DLD group found the production of marked verb forms more challenging than less marked ones. These results are discussed in light of the structural characteristics of Arabic. Future studies would need to include larger sample sizes, investigate other aspects of verb morphology, including both production and comprehension, include other language domains, and consider longitudinal designs to provide more in-depth knowledge of Arabic language acquisition

Nonword repetition performance of Arabic-speaking children with and without Developmental Language Disorder: a study on diagnostic accuracy

Purpose: This study evaluates the effectiveness of a nonword repetition (NWR) task in discriminating between Palestinian Arabic-speaking children with Developmental Language Disorder (DLD) and age-matched typically-developing (TD) children. Methods: Participants were 30 children with DLD aged between 4;00 and 6;10 and 60 TD children aged between 4;00 and 6;8 matched on chronological age. The Arabic version of a Quasi-Universal Nonword Repetition task was administered. The task comprises 30 nonwords that vary in length, presence of consonant clusters (CC) and wordlikeness ratings. Responses were scored using an item-level scoring method. To assess the diagnostic accuracy of the task. ROC curve analysis was conducted to determine the best cut-off point with the highest sensitivity and specificity values and likelihood ratios were calculated. Results: Children with DLD scored significantly lower on the NWR task than their age� matched TD peers. Only the DLD group was influenced by the phonological complexity of the nonwords, with nonwords with two CC being more difficult than nonwords with no or only one CC. For both groups, three-syllable nonwords were repeated less accurately than two and one-syllable nonwords. Also, high word-like nonwords were repeated more accurately than nonwords with low wordlikeness ratings. The best cutoff score had sensitivity and specificity of 93% and highly informative likelihood ratios. Conclusion: NWR was an area of difficulty for Palestinian Arabic-speaking children with DLD. NWR showed excellent discriminatory power in differentiating Arabic-speaking children diagnosed with DLD from their age-matched TD peers. NWR appears to hold promise for clinical use as it is a useful indicator of DLD in Arabic. These results need to be further validated using population-based studies