Purpose: Specific language impairment (SLI; see also developmental language disorder) and dyslexia are separate, yet frequently co-occurring disorders that confer risks to reading comprehension and ...academic achievement. Until recently, most studies of one disorder had little consideration of the other, and each disorder was addressed by different practitioners. However, understanding how the two disorders relate to each other is important for advancing theories about each disorder and improving reading comprehension and academic achievement. The purpose of this clinical focus article is to integrate research on SLI and dyslexia as well as advocate for the consideration of comorbidities in future research and clinical practice. Method: The first section reviews definitions as well as inclusionary and exclusionary criteria for SLI and dyslexia. The second section reviews research demonstrating that SLI and dyslexia are different disorders that often co-occur. Studies examining language, working memory, and academic achievement in children with separate versus co-occurring SLI and dyslexia are reviewed. The final section compares and contrasts school identification frameworks for children with SLI and dyslexia and considers the potential benefits of incorporating broad language skills into response to intervention (RTI) assessment frameworks. Conclusions: Children with weak language skills are at a high risk of experiencing reading problems, but language difficulties are often hidden from view. Directly addressing language skills within school RTI frameworks can help improve the identification and treatment of children with SLI and dyslexia as well as support improved reading comprehension and academic achievement for all students.
Purpose: The purpose of this tutorial is to discuss the language basis of dyslexia in the context of developmental language disorders (DLDs). Whereas most studies have focused on the phonological ...skills of children with dyslexia, we bring attention to broader language skills. Method: We conducted a focused literature review on the language basis of dyslexia from historical and theoretical perspectives with a special emphasis on the relation between dyslexia and DLD and on the development of broader language skills (e.g., vocabulary, syntax, and discourse) before and after the identification of dyslexia. Results: We present clinically relevant information on the history of dyslexia as a language-based disorder, the operational definitions used to diagnose dyslexia in research and practice, the relation between dyslexia and DLD, and the language abilities of children with dyslexia. Conclusions: We discuss 3 clinical implications for working with children with dyslexia in school settings: (a) Children with dyslexia--with and without comorbid DLDs--often have language deficits outside the phonological domain; (b) intervention should target a child's strengths and weaknesses relative to reading outcomes, regardless of diagnostic labels; and (c) those who have dyslexia, regardless of language abilities at the time of diagnosis, may be at risk for slower language acquisition across their lifetime. Longitudinal studies are needed to assess multiple language skills early, at the time of the diagnosis of dyslexia, and years later to better understand the complex development of language and reading in children with dyslexia.
Susan Ellis Weismer
Waisman Center, University of WisconsinMadison
Contact author: Hugh W. Catts, Department of Speech, Language, Hearing, 1000 Sunnyside Avenue, University of Kansas, Lawrence, KS, ...66045. Email: catts{at}ku.edu
PURPOSE: To examine concurrently and retrospectively the language abilities of children with specific reading comprehension deficits ("poor comprehenders") and compare them to typical readers and children with specific decoding deficits ("poor decoders").
METHOD: In Study 1, the authors identified 57 poor comprehenders, 27 poor decoders, and 98 typical readers on the basis of 8th-grade reading achievement. These subgroups' performances on 8th-grade measures of language comprehension and phonological processing were investigated. In Study 2, the authors examined retrospectively subgroups' performances on measures of language comprehension and phonological processing in kindergarten, 2nd, and 4th grades. Word recognition and reading comprehension in 2nd and 4th grades were also considered.
RESULTS: Study 1 showed that poor comprehenders had concurrent deficits in language comprehension but normal abilities in phonological processing. Poor decoders were characterized by the opposite pattern of language abilities. Study 2 results showed that subgroups had language (and word recognition) profiles in the earlier grades that were consistent with those observed in 8th grade. Subgroup differences in reading comprehension were inconsistent across grades but reflective of the changes in the components of reading comprehension over time.
CONCLUSIONS: The results support the simple view of reading and the phonological deficit hypothesis. Furthermore, the findings indicate that a classification system that is based on the simple view has advantages over standard systems that focus only on word recognition and/or reading comprehension.
KEY WORDS: poor comprehenders, specific reading comprehension deficit, simple view of reading, phonological processing, language comprehension deficits
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Purpose: This study examined the production of morphosyntactic markers by school-age children with and without developmental language disorder. Comparisons were made between students who speak ...mainstream American English (MAE) dialects and nonmainstream American English (NMAE) dialects. Method: First- and second-grade students (N = 82) completed assessments of dialect use and language ability, which are designed for students who speak NMAE dialects. Students also completed an experimental production task targeting three morphosyntactic features: past tense "-ed" marking, third-person singular "-s" marking, and plural "-s" marking. Past tense marking and third-person singular are produced differently across MAE and NMAE dialects, whereas plural marking is produced more similarly across dialects. Results: When comparing across dialects, children with typical language skills who spoke NMAE dialects overtly marked past tense and third-person singular less often compared to MAE peers. However, when comparing to same-dialect peers with language disorders, children with typical language skills who spoke NMAE dialects overtly marked these morphosyntactic markers more often than peers with developmental language disorder. Conclusion: The results underscore the importance of considering a child's dialect use when assessing language ability, in particular with measures that include features that are variable in NMAE dialects. At the same time, within-dialect comparisons suggest that a broader set of morphosyntactic features may provide useful information for evaluations of language ability. Future research should investigate the source of these differences, including the extent to which students with language disorders have acquired the social and linguistic factors that condition the use of variable features.
Purpose: This prologue introduces the LSHSS Forum: Vocabulary Across the School Grades. The goals of the forum are to provide an overview of the importance of vocabulary to literacy and academic ...achievement, to review evidence regarding best practices for vocabulary instruction, and to highlight recent research related to word learning with students across different grade levels. Method: The prologue provides a foundational overview of vocabulary's role in literacy and introduces the topics of the other ten articles in the forum. These include clinical focus articles, research reviews, and word-learning and vocabulary intervention studies involving students in elementary grades through college. Conclusion: Children with language and reading disorders experience specific challenges learning new words, but all students can benefit from high-quality vocabulary instruction. The articles in this issue highlight the characteristics of evidence-based vocabulary interventions for children of different ages, ability levels, and language backgrounds and provide numerous examples of intervention activities that can be modified for use in individual, small-group, or large-group instructional settings.
Purpose: This study examined the unique and shared variance that nonword repetition and vocabulary knowledge contribute to children's ability to learn new words. Multiple measures of word learning ...were used to assess recall and recognition of phonological and semantic information. Method: Fifty children, with a mean age of 8 years (range 5-12 years), completed experimental assessments of word learning and norm-referenced assessments of receptive and expressive vocabulary knowledge and nonword repetition skills. Hierarchical multiple regression analyses examined the variance in word learning that was explained by vocabulary knowledge and nonword repetition after controlling for chronological age. Results: Together with chronological age, nonword repetition and vocabulary knowledge explained up to 44% of the variance in children's word learning. Nonword repetition was the stronger predictor of phonological recall, phonological recognition, and semantic recognition, whereas vocabulary knowledge was the stronger predictor of verbal semantic recall. Conclusions: These findings extend the results of past studies indicating that both nonword repetition skill and existing vocabulary knowledge are important for new word learning, but the relative influence of each predictor depends on the way word learning is measured. Suggestions for further research involving typically developing children and children with language or reading impairments are discussed.
We assessed nonword repetition (NWR) skills in 7-9 year-old children with dyslexia (dyslexia-only), developmental language disorder (DLD-only), co-occurring DLD+dyslexia, and typical development (TD) ...with a norm-referenced and an experimental task. The experimental task manipulated phonemic variability (dissimilarity among consonant phonemes within the nonword) and presentation modality (audio-only versus audiovisual) to probe potential phonological processing differences among the groups. Across tasks, the dyslexia-only and DLD-only groups performed similarly to each other and intermediately to the TD and DLD+dyslexia groups. In the experimental task, nonwords with low phonemic variability were produced less accurately in both modalities, and audiovisual presentation facilitated accurate repetition of low phonemic variability nonwords. A lack of a group interaction with phonemic variability or presentation modality suggests similarities, despite group differences, in how underlying phonological representations influence task performance. Overall, results suggest that poor NWR is associated with both dyslexia and DLD, and that co-occurrence compounds this difficulty.
Purpose: The purpose of this study was to determine whether specific language impairment (SLI) and dyslexia are distinct developmental disorders. Method: Study 1 investigated the overlap between SLI ...identified in kindergarten and dyslexia identified in 2nd, 4th, or 8th grades in a representative sample of 527 children. Study 2 examined phonological processing in a subsample of participants, including 21 children with dyslexia only, 43 children with SLI only, 18 children with SLI and dyslexia, and 165 children with typical language/reading development. Measures of phonological awareness and nonword repetition were considered. Results: Study 1 showed limited but statistically significant overlap between SLI and dyslexia. Study 2 found that children with dyslexia or a combination of dyslexia and SLI performed significantly less well on measures of phonological processing than did children with SLI only and those with typical development. Children with SLI only showed only mild deficits in phonological processing compared with typical children. Conclusions: These results support the view that SLI and dyslexia are distinct but potentially comorbid developmental language disorders. A deficit in phonological processing is closely associated with dyslexia but not with SLI when it occurs in the absence of dyslexia. (Contains 3 tables, 3 figures, and 2 footnotes.)
We examined how children (N = 448) with separate or co-occurring developmental language disorder (DLD) and dyslexia performed on school-based measures of academic functioning between second and ...fourth grades. Children were recruited from 1 school district in the U.S. state of South Carolina via classroom screenings and met common research criteria for DLD and dyslexia. Growth curve models were used to examine the overall form of growth and differences between groups. Children with DLD and/or dyslexia in second grade showed early and persistent deficits on school-administered measures of reading and math. In second grade, children with typical development (TD) scored significantly higher than children with dyslexia-only and DLD-only, who did not differ from each other. Children with DLD+dyslexia scored significantly lower than all other groups. Only small differences in growth rates were observed, and gaps in second grade did not close. Despite lower academic performance, few children (20%–27%) with dyslexia and/or DLD had received specialized support services. Children with DLD-only received services at less than half the rate of dyslexia-only or DLD+dyslexia despite similar impacts on academic performance. Evidence of significant and persistent functional impacts in the context of low rates of support services in these children—especially those with DLD-only—highlights the need to raise awareness of these disorders.
Purpose: The study aims to determine whether brief, group-administered screening measures can reliably identify second-grade children at risk for language impairment (LI) or dyslexia and to examine ...the degree to which parents of affected children were aware of their children's difficulties. Method: Participants (N = 381) completed screening tasks and assessments of word reading, oral language, and nonverbal intelligence. Their parents completed questionnaires that inquired about reading and language development. Results: Despite considerable overlap in the children meeting criteria for LI and dyslexia, many children exhibited problems in only one domain. The combined screening tasks reliably identified children at risk for either LI or dyslexia (area under the curve = 0.842), but they were more accurate at identifying risk for dyslexia than LI. Parents of children with LI and/or dyslexia were frequently unaware of their children's difficulties. Parents of children with LI but good word reading skills were the least likely of all impairment groups to report concerns or prior receipt of speech, language, or reading services. Conclusions: Group-administered screens can identify children at risk of LI and/or dyslexia with good classification accuracy and in less time than individually administered measures. More research is needed to improve the identification of children with LI who display good word reading skills.
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