Performance of children on the Turkish Nonword Repetition Test: Effect of word similarity, word length, and scoring

Beyond Language Scores: How Language Exposure Informs Assessment of Nonword Repetition, Vocabulary and Narrative Macrostructure in Bilingual Turkish/Swedish Children with and without Developmental Language Disorder

As in many other countries, baseline data concerning the linguistic development of bilingual children in Sweden are lacking, and suitable methods for identifying developmental language disorder (DLD) in bilinguals are lacking as well. This study presents reference data from 108 typically developing (TD) Turkish/Swedish-speaking children aged 4;0-8;1, for a range of language tasks developed specifically for the assessment of bilinguals (LITMUS test battery, COST Action IS0804). We report on different types of nonword repetition (NWR) tasks (language-specific and language-independent), receptive and expressive vocabulary (Cross-Linguistic Lexical Tasks, CLTs), and narrative macrostructure comprehension and production (Multilingual Assessment Instrument for Narratives, MAIN) in Turkish, the children's home language, and in Swedish, the language of schooling and society. Performance was investigated in relation to age, language exposure, type of task, and (for NWR and narratives) vocabulary size. There was a positive development with age for all tasks, but effects of language exposure and vocabulary size differed between tasks. Six bilingual Turkish/Swedish children with DLD were individually compared to the TD children. TD/DLD performance overlapped substantially, particularly for NWR, and more so for the production than the comprehension tasks. Surprisingly, the discriminatory potential was poor for both language-specific and language-independent NWR. DLD case studies underscored the importance of interpreting language scores in relation to exposure history, and the need for an increased emphasis on functional language skills as reported by parents and teachers when assessing and diagnosing DLD in bilinguals.

Learnability Advantage of Segmental Repetitions in Word Learning

To date, research on wordform learning biases has mostly focused on language-dependent factors, such as the phonotactics and neighborhood density of the language(s) known by the learner. Domain-general biases, by contrast, have received little attention. In this study, we focus on one such bias-an advantage for string-internal repetitions-and examine its effects on wordform learning. Importantly, we consider whether any type of segmental repetition is equally beneficial for word recall, or whether learning is favored more or only by repeated consonants, in line with previous research indicating that consonants play a larger role than vowels in lexical processing. In Experiment 1, adult English speakers learned artificial consonant-vowel-consonant-vowel words containing either a repeated consonant (e.g., /sesu/, "c-rep"), a repeated vowel (e.g., /sepe/, "v-rep"), or dissimilar consonants and vowels (e.g., /sepu/, "no-rep"). Recall results showed no advantage for v-reps but higher accuracy for c-reps compared with no-reps. In Experiment 2, participants performed a label preference task with the same stimuli. The results showed dispreference for both c-reps and v-reps relative to no-reps, indicating that the results of Experiment 1 are independent of wordlikeness effects. These outcomes reveal that there is a form-learning bias for words with identical consonants but not for words with identical vowels, suggesting that a domain-general advantage for repetitions within strings is modulated by a language-specific processing bias for consonants.

Using Nonword Repetition to Identify Developmental Language Disorder in Monolingual and Bilingual Children: A Systematic Review and Meta-Analysis

Purpose A wealth of studies has assessed the diagnostic value of the nonword repetition task (NWRT) for the detection of developmental language disorder (DLD) in the clinical context of speech and language therapy, first in monolingual children and, more recently, in bilingual children. This review article reviews this literature systematically and conducts a meta-analysis on the discriminative power of this type of task in both populations. Method Three databases were used to select articles based on keyword combinations, which were then reviewed for relevance and methodological rigor based on internationally recognized checklists. From an initial pool of 488 studies, 46 studies were selected for inclusion in the systematic review, and 35 of these studies could be included in a meta-analysis. Results Most of the articles report significant discrimination between children with and without DLD in both monolingual and bilingual contexts, and the meta-analysis shows a large mean effect size. Three factors (age of the child, linguistic status, and language specificity of the task) yielded enough quantitative data for further exploration. Subgroups analysis shows variance in effect sizes, but none of the three factors, neither their interactions, were significant in a metaregression. We discuss how other, less explored factors (e.g., nature of the stimuli, scoring methods) could also contribute to differences in results. Sensitivity and specificity analyses reported in 33 studies confirmed that, despite possible effect size differences, the diagnostic accuracy of the NWRT is generally near thresholds considered to be discriminatory. It generally increases when it is combined with other tasks (e.g., parental questionnaire). Conclusions This review indicates that the NWRT is a promising diagnostic tool to identify children with DLD in monolingual and bilingual contexts with a large mean effect size. However, it seems necessary to choose the precise NWRT materials based on the children's language background and to complement the assessment sessions with other tools in order to ensure diagnosis and to obtain complete language profile of the child. Supplemental Material https://doi.org/10.23641/asha.15152370.

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. Method Participants were 30 children with DLD aged between 4;0 and 6;10 (years;months) and 60 TD children aged between 4;0 and 6;8 matched on chronological age. The Arabic version of a Quasi-Universal NWR task was administered. The task comprises 30 nonwords that vary in length, presence of consonant clusters (CCs) and wordlikeness ratings. Responses were scored using an item-level scoring method to assess the diagnostic accuracy of the task. Receiver operating characteristic curve analysis was conducted to determine the best cutoff 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. Conclusions 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. Supplemental Material https://doi.org/10.23641/asha.14880360.

Vowel dyslexia in Turkish: A window to the complex structure of the sublexical route

We report on developmental vowel dyslexia, a type of dyslexia that selectively affects the reading aloud of vowel letters. We identified this dyslexia in 55 Turkish-readers aged 9-10, and made an in-depth multiple-case analysis of the reading of 17 participants whose vowel dyslexia was relatively selective. These participants made significantly more vowel errors (vowel substitution, omission, migration, and addition) than age-matched controls, and significantly more errors in vowel letters than in consonants. Vowel harmony, a pivotal property of Turkish phonology, was intact and the majority of their vowel errors yielded harmonic responses. The transparent character of Turkish orthography indicates that vowel dyslexia is not related to ambiguity in vowel conversion. The dyslexia did not result from a deficit in the phonological-output stage, as the participants did not make vowel errors in nonword repetition or in repeating words they had read with a vowel error. The locus of the deficit was not in the orthographic-visual-analyzer either, as their same-different decision on words differing in vowels was intact, and so was their written-word comprehension. They made significantly more errors on nonwords than on words, indicating that their deficit was in vowel processing in the sublexical route. Given that their single-vowels conversion was intact, and that they showed an effect of the number of vowels, we conclude that their deficit is in a vowel-specific buffer in the sublexical route. They did not make vowel errors within suffixes, indicating that suffixes are converted as wholes in a separate sublexical sub-route. These results have theoretical implications for the dual-route model: they indicate that the sublexical route converts vowels and consonants separately, that the sublexical route includes a vowel buffer, and a separate morphological conversion route. The results also indicate that types of dyslexia can be detected in transparent languages given detailed error-analysis and dyslexia-relevant stimuli.

Developmental Letter Position Dyslexia in Turkish, a Morphologically Rich and Orthographically Transparent Language

We present the first report of a specific type of developmental dyslexia in Turkish, letter position dyslexia (LPD). LPD affects the encoding of letter positions, leading to letter migrations within words. In a multiple case study of 24 Turkish-speaking children with developmental LPD, we examined in detail the characteristics of this dyslexia and explored its manifestation in Turkish. We used migratable words, in which a migration creates another existing word (e.g., signer-singer), which exposed the migration errors of the participants. In sharp contrast with the common assumption that dyslexics in transparent languages, including Turkish, do not make reading errors, we have shown that right stimuli can detect even up to 30% reading errors. The participants made migrations in reading aloud, comprehension, lexical decision, and same-different tasks, in both words and non-words. This indicates that their deficit is in the orthographic-visual analysis stage, a stage that precedes the orthographic input lexicon and is shared by the lexical and non-lexical routes. Their repetition of non-words and migratable words was normal, indicating that their phonological output stages are intact. They did not make digit migrations in reading numbers, indicating that the orthographic-visual analyzer deficit is orthographic-specific. The properties of Turkish allowed us to examine two issues that bear on the cognitive model of reading: consonant-consonant transpositions were far more frequent than consonant-vowel and vowel-vowel migrations. This indicates that the orthographic-visual analyzer already classifies letters into consonants and vowels, before or together with letter position encoding. Furthermore, Turkish is very rich morphologically, which has allowed us to examine the effect of the morphological structure of the target word on migrations. We found that there was no morphological effect on migrations: morphologically complex words did not yield more (nor fewer) migrations than monomorphemic ones, migrations crossed morpheme boundaries and did not preserve the morphological structure of the target word. This suggests that morphological analysis follows the letter-position encoding stage.

Shortened Nonword Repetition Task (NWR-S): A Simple, Quick, and Less Expensive Outcome to Identify Children With Combined Specific Language and Reading Impairment

PURPOSE

The purpose of this research note was to validate a simplified version of the Dutch nonword repetition task (NWR; Rispens & Baker, 2012). The NWR was shortened and scoring was transformed to correct/incorrect nonwords, resulting in the shortened NWR (NWR-S).

METHOD

NWR-S and NWR performance were compared in the previously published data set of Rispens and Baker (2012; N = 88), who compared NWR performance in 5 participant groups: specific language impairment (SLI), reading impairment (RI), both SLI and RI, one control group matched on chronological age, and one control group matched on language age.

RESULTS

Analyses of variance showed that children with SLI + RI performed significantly worse than other participant groups in NWR-S, just as in NWR. Logistic regression analyses showed that both tasks can predict an SLI + RI outcome. NWR-S holds a sensitivity of 82.6% and a specificity of 95.4% in identifying children with SLI + RI. The sensitivity of the original NWR is 87.0% with a specificity of 87.7%.

CONCLUSIONS

As the original NWR, the NWR-S comprising a subset of 22 nonwords scored with a simplified scoring system can identify children with combined SLI and RI while saving a significant amount of the needed assessment time.

SUPPLEMENTAL MATERIALS

https://doi.org/10.23641/asha.5150116.

Tutorial: Speech Assessment for Multilingual Children Who Do Not Speak the Same Language(s) as the Speech-Language Pathologist

PURPOSE

The aim of this tutorial is to support speech-language pathologists (SLPs) undertaking assessments of multilingual children with suspected speech sound disorders, particularly children who speak languages that are not shared with their SLP.

METHOD

The tutorial was written by the International Expert Panel on Multilingual Children's Speech, which comprises 46 researchers (SLPs, linguists, phoneticians, and speech scientists) who have worked in 43 countries and used 27 languages in professional practice. Seventeen panel members met for a 1-day workshop to identify key points for inclusion in the tutorial, 26 panel members contributed to writing this tutorial, and 34 members contributed to revising this tutorial online (some members contributed to more than 1 task).

RESULTS

This tutorial draws on international research evidence and professional expertise to provide a comprehensive overview of working with multilingual children with suspected speech sound disorders. This overview addresses referral, case history, assessment, analysis, diagnosis, and goal setting and the SLP's cultural competence and preparation for working with interpreters and multicultural support workers and dealing with organizational and government barriers to and facilitators of culturally competent practice.

CONCLUSION

The issues raised in this tutorial are applied in a hypothetical case study of an English-speaking SLP's assessment of a multilingual Cantonese- and English-speaking 4-year-old boy. Resources are listed throughout the tutorial.

Diagnostic accuracy of repetition tasks for the identification of specific language impairment (SLI) in bilingual children: evidence from Russian and Hebrew

BACKGROUND

Previous research demonstrates that repetition tasks are valuable tools for diagnosing specific language impairment (SLI) in monolingual children in English and a variety of other languages, with non-word repetition (NWR) and sentence repetition (SRep) yielding high levels of sensitivity and specificity. Yet, only a few studies have addressed the diagnostic accuracy of repetition tasks in bilingual children, and most available research focuses on English-Spanish sequential bilinguals.

AIMS

To evaluate the efficacy of three repetition tasks (forward digit span (FWD), NWR and SRep) in order to distinguish mono- and bilingual children with and without SLI in Russian and Hebrew.

METHODS & PROCEDURES

A total of 230 mono- and bilingual children aged 5;5-6;8 participated in the study: 144 bilingual Russian-Hebrew-speaking children (27 with SLI); and 52 monolingual Hebrew-speaking children (14 with SLI) and 34 monolingual Russian-speaking children (14 with SLI). Parallel repetition tasks were designed in both Russian and Hebrew. Bilingual children were tested in both languages.

OUTCOMES & RESULTS

The findings confirmed that NWR and SRep are valuable tools in distinguishing monolingual children with and without SLI in Russian and Hebrew, while the results for FWD were mixed. Yet, testing of bilingual children with the same tools using monolingual cut-off points resulted in inadequate diagnostic accuracy. We demonstrate, however, that the use of bilingual cut-off points yielded acceptable levels of diagnostic accuracy. The combination of SRep tasks in L1/Russian and L2/Hebrew yielded the highest overall accuracy (i.e., 94%), but even SRep alone in L2/Hebrew showed excellent levels of sensitivity (i.e., 100%) and specificity (i.e., 89%), reaching 91% of total diagnostic accuracy.

CONCLUSIONS & IMPLICATIONS

The results are very promising for identifying SLI in bilingual children and for showing that testing in the majority language with bilingual cut-off points can provide an accurate classification.