Nonword Repetition Abilities Research Articles

Non‐word repetition in adolescents with specific language impairment (SLI)

Non-word repetition (NWR) difficulties are common, but not universal, among children with specific language impairment (SLI). However, older children and adolescents with SLI have rarely been studied. Studies disagree on the relationship between NWR difficulties and difficulties with other areas of language and literacy. There is also no consensus about the underlying reason for the difficulties (some) children with SLI have with NWR. Some scholars argue that difficulties with phonological short-term memory or storage cause NWR and other language difficulties, whereas others argue that difficulties with NWR may be due more to difficulties with phonological representations. To investigate NWR abilities and their relationship to other language and literacy abilities in a group of older children with SLI and typically developing controls. To investigate the relative effects of increasing phonological complexity and the number of syllables on the ability of the participants to repeat non-words. An NWR test (The Test of Phonological Structure; TOPhS), which systematically varies phonological complexity, was administered to 15 participants with SLI (aged 11-15 years), 30 language and 15 age controls. Standardized language and literacy tests and a specific test of verb agreement and tense marking (Verb Agreement and Tense Test; VATT) were also administered. The participants with SLI showed a bimodal distribution: half achieved age-appropriate NWR, while half scored significantly below language and age controls (d > 7). The two groups of participants with SLI (high versus low scorers) only differed in NWR (d > 5) and agreement (d > 3) and tense marking (d > 2.5), not on the standardized language and literacy measures administered. NWR was also highly correlated with verb agreement (r= 0.97) and tense marking (r= 0.89) among participants with SLI, but not among controls (r= 0.16 and 0.30 respectively). Phonological complexity was related to NWR accuracy, particularly among participants with SLI. The number of syllables had no independent effect on NWR performance for any group. Some children with SLI (who have good NWR) have language difficulties unrelated to any of the factors underlying NWR. Others have a (probably additional) deficit which affects NWR and also leads to greater difficulties with verb agreement and tense marking. The results indicate that difficulties with this particular NWR test are more likely to be due to a deficit with phonology per se, rather than with phonological short-term memory or storage.

Psychometric Analysis of the Diagnostic Evaluation of Language Variation Assessment.

This study investigated the psychometrics of the Diagnostic Evaluation of Language Variation–Screening Test (DELV-S) test using confirmatory factor analysis, item response theory, and differential item functioning (DIF). Responses from 1,764 students in kindergarten through second grade were used in the study, with results indicating that the DELV-S is multidimensional and measures syntactic skills and nonword repetition ability. Item response theory suggested that most items were easy and that the measured skills were most reliable for students who had low language abilities. Standardized effect sizes for DIF suggested small differences existed on syntactic skills between white and minority students. Scores were vertically scaled to produce reference tables to assess performance at specific points in time, as well as growth over time.

Impairment in non-word repetition: a marker for language impairment or reading impairment?

A deficit in non-word repetition (NWR), a measure of short-term phonological memory proposed as a marker for language impairment, is found not only in language impairment but also in reading impairment. We evaluated the strength of association between language impairment and reading impairment in children with current, past, and no language impairment and assessed any differential impairment of NWR, compared with two other tests of verbal memory in children with language impairment with and without reading impairment. Our sample comprised children aged 6-16y 11mo participating in a study of the genetics of language impairment: 78 children from 68 families (53 males, 25 females) with current language impairment (C-LI), compared with their 74 siblings: 25 children (18 males, seven females) with a past history of language impairment and 49 children (27 males, 22 females) who had never had a language impairment. The tests used were the Clinical Evaluation of Language Fundamentals (CELF III), the Children's Test of Non-word Repetition (CN-Rep), the Wide Range Assessment of Memory and Learning (WRAML) verbal memory index, the Wechsler Intelligence Scale for Children-III (WISC-III) digit span, and the Wechsler Objective Reading Dimensions (WORD(UK) ). Reading impairment was present in two-thirds of the children with current language impairment. NWR deficits were significantly worse in children with language impairment who had reading impairment in reading decoding (p=0.007 and 0.004 - average group compared with borderline and definitely impaired groups respectively) or spelling (p=0.002 and 0.005 - average group compared with borderline and severely impaired groups respectively) (not correlated with severity of language impairment) but not comprehension impairment. In contrast, WISC digit span and WRAML verbal memory were impaired in all children with language impairment and did not differentiate those who also had reading impairment. We suggest that current NWR ability may be a marker of a process specifically underlying language impairment, co-occurring with reading impairment involving reading decoding and spelling, rather than a generic correlate of language impairment. Other verbal memory deficits appear to be pervasive in children with language impairment.

“The dog chase the cat”: Grammaticality judgments by Hungarian-speaking children with language impairment

In a previous study of language production, a group of Hungarian-speaking children with language impairment (LI) committed a larger number of errors than typically developing peers on verb inflections that mark person, number, tense, and definiteness (Lukács et al. 2009b). However, the error forms produced often differed from the correct form by only a single dimension (e.g., person, number, tense, or definiteness) with no single dimension proving consistently problematic. In the present study, we sought to determine whether a similar pattern applied to the children’s understanding of verb inflections, as reflected in a grammaticality judgment task. We compared the performance of 17 Hungarian-speaking children with language impairment (LI) between ages 8;0 and 11;9 with typically developing children between 6;10 and 11;1 years individually matched on receptive vocabulary raw scores (VC) and also to a control group of children matched on chronological age (AC; between 8;1–12;1). We obtained grammaticality judgments for 68 sentences, including 56 ill-formed sentences that contained a single error of person, number, tense, definiteness, or morphophonology. As the AC group performed at ceiling, the analysis focused on comparisons between the LI and VC groups. Besides comparing accuracy scores in the two groups, we tested how well performance could be predicted by a test of grammatical comprehension (TROG) and a measure of nonword repetition ability obtained prior to the administration of the grammaticality judgment task. There were no significant group differences in the accuracy of grammaticality judgments. Both groups recognized well-formed sentences, and agreement errors of number, person or definiteness, significantly more accurately than tense or morphophonological errors. Although there was no difference between performance levels of the LI and the VC groups, we found differences between the two groups in the types of measures that were most closely tied to performance on the grammaticality judgment task. Performance in the LI group was strongly associated with nonword repetition span, while in the VC group, TROG performance was associated with grammaticality judgment performance. These results suggest that the same level and pattern of performance can be supported by different background mechanisms in typical and atypical language development.

Nonword repetition in children and adults: effects on movement coordination

Hearing and repeating novel phonetic sequences, or novel nonwords, is a task that taps many levels of processing, including auditory decoding, phonological processing, working memory, speech motor planning and execution. Investigations of nonword repetition abilities have been framed within models of psycholinguistic processing, while the motor aspects, which also are critical for task performance, have been largely ignored. We focused our investigation on both the behavioral and speech motor performance characteristics of this task as performed in a learning paradigm by 9- and 10-year-old children and young adults. Behavioral (percent correct productions) and kinematic (movement duration, lip aperture variability - an index of the consistency of inter-articulator coordination on repeated trials) measures were obtained in order to investigate the short-term (Day 1, first five vs. next five trials) and longer-term (Day 1 vs. Day 2, first five vs. next five trials) changes associated with practice within and between sessions. Overall, as expected, young adults showed higher levels of behavioral accuracy and greater levels of coordinative consistency than the children. Both groups, however, showed a learning effect, such that in general, later Day 1 trials and Day 2 trials were shorter in duration and more consistent in coordination patterns than Day 1 early trials. Phonemic complexity of the nonwords had a profound effect on both the behavioral and speech motor aspects of performance. The children showed marked learning effects on all nonwords that they could produce accurately, while adults' performance improved only when challenged by the more complex nonword stimuli in the set. The findings point to a critical role for speech motor processes within models of nonword repetition and suggest that young adults, similar to children, show short- and longer-term improvements in coordinative consistency with repeated production of complex nonwords. There is also a clear developmental change in nonword production performance, such that less complex novel sequences elicit changes in speech motor performance in children, but not in adults.

Non‐word repetition and literacy in Dutch children at‐risk of dyslexia and children with SLI: results of the follow‐up study

This study related the non-word repetition (NWR) abilities of 4-year-old children at-risk of dyslexia and children with specific language impairment (SLI) to their reading abilities at age eight. The results show that the SLI group obtained the lowest NWR score and the at-risk group performed in-between the control and SLI group. Approximately half of the at-risk and SLI group showed reading difficulties. Literacy and NWR abilities were correlated for the at-risk group, but not for the SLI group. The findings point toward differences between the groups and suggest that dyslexia and SLI should not be treated as a similar disorder.

Does phonological short-term memory causally determine vocabulary learning? Toward a computational resolution of the debate

The relationship between nonword repetition ability and vocabulary size and vocabulary learning has been a topic of intense research interest and investigation over the last two decades, following the demonstration that nonword repetition accuracy is predictive of vocabulary size (Gathercole & Baddeley, 1989). However, the nature of this relationship is not well understood. One prominent account posits that phonological short-term memory (PSTM) is a causal determinant both of nonword repetition ability and of phonological vocabulary learning, with the observed correlation between the two reflecting the effect of this underlying third variable (e.g., Baddeley, Gathercole, & Papagno, 1998). An alternative account proposes the opposite causality: that it is phonological vocabulary size that causally determines nonword repetition ability (e.g., Snowling, Chiat, & Hulme, 1991). We present a theory of phonological vocabulary learning, instantiated as a computational model. The model offers a precise account of the construct of PSTM, of performance in the nonword repetition task, of novel word form learning, and of the relationship between all of these. We show through simulation not only that PSTM causally affects both nonword repetition accuracy and phonological vocabulary size, but also that phonological vocabulary size causally affects nonword repetition ability. The plausibility of the model is supported by the fact that its nonword repetition accuracy displays effects of phonotactic probability and of nonword length, which have been taken as evidence for causal effects on nonword repetition accuracy of phonological vocabulary knowledge and PSTM, respectively. Thus the model makes explicit how the causal links posited by the two theoretical perspectives are both valid, in the process reconciling the two perspectives, and indicating that an opposition between them is unnecessary.

CMIP and ATP2C2 Modulate Phonological Short-Term Memory in Language Impairment

Specific language impairment (SLI) is a common developmental disorder characterized by difficulties in language acquisition despite otherwise normal development and in the absence of any obvious explanatory factors. We performed a high-density screen of SLI1, a region of chromosome 16q that shows highly significant and consistent linkage to nonword repetition, a measure of phonological short-term memory that is commonly impaired in SLI. Using two independent language-impaired samples, one family-based (211 families) and another selected from a population cohort on the basis of extreme language measures (490 cases), we detected association to two genes in the SLI1 region: that encoding c-maf-inducing protein (CMIP, minP = 5.5 × 10−7 at rs6564903) and that encoding calcium-transporting ATPase, type2C, member2 (ATP2C2, minP = 2.0 × 10−5 at rs11860694). Regression modeling indicated that each of these loci exerts an independent effect upon nonword repetition ability. Despite the consistent findings in language-impaired samples, investigation in a large unselected cohort (n = 3612) did not detect association. We therefore propose that variants in CMIP and ATP2C2 act to modulate phonological short-term memory primarily in the context of language impairment. As such, this investigation supports the hypothesis that some causes of language impairment are distinct from factors that influence normal language variation. This work therefore implicates CMIP and ATP2C2 in the etiology of SLI and provides molecular evidence for the importance of phonological short-term memory in language acquisition.

Mismatch Response to Polysyllabic Nonwords: A Neurophysiological Signature of Language Learning Capacity

BackgroundThe ability to repeat polysyllabic nonwords such as “blonterstaping” has frequently been shown to correlate with language learning ability but it is not clear why such a correlation should exist. Three alternative explanations have been offered, stated in terms of differences in: (a) perceptual ability; (b) efficiency of phonological loop functioning; (c) pre-existing vocabulary knowledge and/or articulatory skills. In the present study, we used event-related potentials to assess the contributions from these three factors to explaining individual variation in nonword repetition ability.Methodology/Principal Findings59 adults who were subdivided according to whether they were good or poor nonword-repeaters participated. Electrophysiologically measured mismatch responses were recorded to changes in consonants as participants passively listened to a repeating four syllable CV-string. The consonant change could occur in one of four positions along the CV-string and we predicted that: (a) if nonword repetition depended purely on auditory discrimination ability, then reduced mismatch responses to all four consonant changes would be observed in the poor nonword-repeaters, (b) if it depended on encoding or decay of information in a capacity-limited phonological store, then a position specific decrease in mismatch response would be observed, (c) if neither cognitive capacity was involved, then the two groups of participants would provide equivalent mismatch responses. Consistent with our second hypothesis, a position specific difference located on the third syllable was observed in the late discriminative negativity (LDN) window (230–630 ms post-syllable onset).Conclusions/SignificanceOur data thus confirm that people who are poorer at nonword repetition are less efficient in early processing of polysyllabic speech materials, but this impairment is not attributable to deficits in low level auditory discrimination. We conclude by discussing the significance of the observed relationship between LDN amplitude and nonword repetition ability and describe how this relatively little understood ERP component provides a biological window onto processes required for successful language learning.

Uses and interpretations of non‐word repetition tasks in children with and without specific language impairments (SLI)

The non-word repetition task (NRT) has gained wide acceptance in describing language acquisition in both children with normal language development (NL) and children with specific language impairments (SLI). This task has gained wide acceptance because it so closely matches the phonological component of word learning, and correlates with measures of phonological working memory, a deficit in which is hypothesized to underlie SLI. Recent uses of the NRT seem to accept it as a measure of phonological working memory capacity in spite of the fact that researchers have consistently acknowledged that the task taps many language processes, including speech perception, phonological encoding, phonological memory, phonological assembly and articulation. This paper reviews the literature on the use of the non-word repetition task (NRT) in children with NL and children with SLI, emphasizing the component skills necessary for successful repetition. For children with NL, discussion has focused on (1) the relationship between non-word repetition ability and vocabulary, and (2) lexical and sublexical influences on repetition accuracy. For children with SLI, discussion has focused on these factors as well, but has also considered other component skills that support non-word repetition. Researchers have examined speech perception and discrimination, phonological encoding, phonological memory, phonological assembly, motor planning, and articulation, and have found evidence that children with SLI exhibit impairments in each of these supporting skills. Because repetition accuracy depends on lexical and sublexical properties, the NRT can be used to examine the structural properties of the lexicon in both children with NL and with SLI. Further, because the task taps so many underlying skills, it is a powerful tool that can be used to identify children with language impairments.

Nonword repetition ability of children who do and do not stutter and covert repair hypothesis

Stuttering has a life span incidence and it significantly impacts academic, social, emotional and vocational achievements of patients who stutter. The purpose of the present study was to examine phonological encoding in young children who stutter (CWS) during a non word repetition task and to test the covert repair hypothesis (CRH) and phonological skills in Persian native children. The study was conducted among 12 CWS and 12 children who do not stutter (CWNS) between the ages of 5.1 and 7.10 at the rehabilitation clinics in Tehran. A list of 40 bisyllabic and trisyllabic nonwords was used in a nonword repetition task to collect information about the following dependent variables: (a) reaction times (RTs), (b) the number of phonological errors (PEs) and (c) nonword length. An independent sample T-test was performed to compare means of PEs and RTs between the two groups and a paired t-test for analysis of nonword length impacts. Results indicated that the CWS had a slightly poor performance than CWNS but there was no significant difference between the groups. Also, the differences between bisyllabic and trisyllabic nonwords were significant for phonological errors but not for reaction times. In general, it is concluded that CWS might not have a gross problem in phonological retrieval of the novel phonological context even with increase in syllable length. Also, some predictions of CRH were not supported by this research. However, further research into this possibility may shed light on the emergence and characteristics of childhood stuttering.

Nonword repetition and language learning disorders: A developmental contingency framework

In 1990 Gathercole and Baddeley proposed a strong hypothesis that has generated a wealth of research in the field of language development and disorder. The hypothesis was that phonological memory, as indexed by nonword repetition, is causally related to vocabulary development. Support for the hypothesis came from an impressive range of longitudinal, correlational, and laboratory training studies, and from studies of specific language impairment (SLI). However, more recently, Gathercole, Tiffany, Briscoe, Thorn, and The ALSPAC Team (2005), directly tested the causal hypothesis by following a cohort of children from age 5 to 8 years. Contrary to prediction, children with poor nonword repetition abilities at age 5 had normal vocabulary at the age of 8.

Nonword recall and phonemic discrimination in four‐ to six‐year‐old children

Previous research has established that the degree of ‘wordlikeness’ of nonwords affects young children's nonword repetition performance. Experiment 1 examined the possibility that output processes are responsible for the wordlikeness effect by using a probed recall procedure. Wordlikeness was defined in terms of phonological neighbourhood density, although this measure was found to be related to the traditional measure of wordlikeness involving adult ratings. A significant effect of number of phonological neighbours/wordlikeness was observed in favour of nonwords with many neighbours. In Experiments 2 and 3 the wordlikeness effect was qualified by a significant interaction with nonword repetition ability. Children with poorer repetition ability were affected by number of neighbours/wordlikeness, while children with better repetition ability were not. Children with poorer repetition ability were significantly poorer than the better repeaters with nonwords with few neighbours. The results were interpreted in terms of theories of phonological development that suggest progressive segmentation of lexical representations. In Experiment 4 the relationship of children's nonword repetition ability to phonemic discrimination ability was investigated. The results demonstrated that children with better nonword repetition ability had superior phonemic discrimination performance than children with poorer nonword repetition ability.

Contrasting contributions of phonological short‐term memory and long‐term knowledge to vocabulary learning in a foreign language

The contributions of phonological short‐term memory and existing foreign vocabulary knowledge to the learning of new words in a second language were compared in a sample of 40 Greek children studying English at school. The children's speed of learning new English words in a paired‐associate learning task was strongly influenced by their current English vocabulary, but was independent of phonological memory skill, indexed by nonword repetition ability. However, phonological memory performance was closely linked to English vocabulary scores. The findings suggest that in learners with considerable familiarity with a second language, foreign vocabulary acquisition is mediated largely by use of existing knowledge representations.

Nonword repetition abilities of children who stutter: an exploratory study

Past research has suggested that children who stutter (CWS) may have less well-developed language skills than fluent children, and that such relative linguistic deficiencies may play a role in precipitating their disfluencies. However, data to support this position are primarily derived from results of standardized diagnostic inventories, which are originally designed to identify frank language impairment. Nonword repetition has emerged as a more sensitive measure of children's linguistic abilities. In this exploratory study, eight CWS (mean age 5:10, range 4:3–8:4) were compared to eight normally developing children (ND) (mean age 5:9, range 4:1–8:4) in their ability to repeat the nonwords of the Children's Test of Nonword Repetition. CWS performed more poorly than NS on measures of Number of Words Correct and Number of Phoneme Errors at all nonword lengths, although statistical differences were observed only for 3-syllable nonwords. When lexical stress of the nonwords was varied to a non-English stress pattern, all participants repeated the stimuli with less accuracy, and the CWS again exhibited more errors than NS. Fluency for the CWS group did not change systematically with increasing nonword length. These preliminary findings are interpreted in light of a number of extant theories of the underlying deficit in childhood stuttering. We conclude that children who stutter may have diminished ability to remember and/or reproduce novel phonological sequences, and that further investigation into this possibility may shed light on the emergence and characteristics of childhood stuttering. Educational objectives: After completing this activity, the learner will: (1) be able to evaluate the research support for a linguistic component to stuttering; (2) describe the use of nonword repetition as an experimental and assessment device with children with SLI and children who stutter; (3) suggest future directions for research to further refine the potential role that linguistic encoding plays in the etiology and persistence of stuttering.

Nonword repetition, phonological memory, and vocabulary: A reply to Snowling, Chiat, and Hulme

The opportunity taken by Snowling, Chiat, and Hulme to step into the debate concerning the nature of the relationship between nonword repetition abilities and vocabulary acquisition in young children should be welcomed. Vocabulary size is strongly associated with a range of abilities, including general intelligence scores, reading ability, reading comprehension, and school success (e.g., Anderson & Freebody, 1981) and as a consequence, vocabulary knowledge provides the major index of verbal intelligence in many standardized ability tests used with both children and adults. Given the weight attached by psychologists to vocabulary knowledge, it seems surprising that until recently the cognitive processes underpinning word learning had been largely neglected. Any progress in understanding the psychological constraints in vocabulary development, whether it takes the form of informed theoretical debate or further empirical work, should therefore be encouraged.