Children's Nonword Repetition Research Articles

Exploring vowel errors produced in nonword repetition in children with speech and language disorders.

Accurate nonword repetition (NWR) is contingent on many underlying skills, including encoding, memory and motor planning and programming. Though vowel errors are frequently associated with childhood apraxia of speech (CAS), several recent studies have found that children with developmental language disorder (DLD) produce high rates of vowel errors in NWR tasks. This retrospective analysis explored whether the overall frequency and types of vowel errors produced in NWR distinguish children with DLD, children with CAS, children with speech sound disorder (SSD) and children with typical development (TD). We present data for 24 children (six per DLD, CAS, SSD and TD groups), ranging in age from 50-92 months. Children with DLD, CAS and SSD showed similar articulation scores and children with DLD and children with CAS showed similar expressive language scores. Total vowel errors, total monophthong errors, monophthong substitutions, diphthongization errors, total diphthong errors, diphthong substitutions and diphthong reduction errors were calculated by syllable length and group. Repeated measures analyses of variance were used to examine group differences. Children with DLD and children with CAS produced a higher frequency of total vowel errors compared to children with TD. Children with DLD produced more total monophthong errors than children with TD. Children with DLD and children with CAS produced more total diphthong errors than children with TD. For children with DLD, these were characterised by diphthong substitutions. For children with CAS, these were characterised by diphthong substitutions and diphthong reduction errors. For all measures, error rates in children with SSD did not significantly differ from any of the other three groups. Preliminary evidence indicates that children with DLD and children with CAS both show high rates of vowel errors in NWR tasks and weaknesses in encoding and memory. For children with CAS, additional motor planning difficulties are associated with an increased likelihood to reduce diphthongs. Children with SSD show more mild processing difficulties than children with DLD and children with CAS, though they do not perform as well as TD peers. Future work should replicate and further specify the processing weaknesses that affect vowel accuracy in NWR tasks in a larger sample. What is already known on the subject Nonword repetition (NWR) tasks are often included in diagnostic batteries to identify children with developmental language disorder (DLD). Poor performance on these tasks have historically been attributed to phonological working memory deficits in children with DLD. However, repeating nonwords relies on a number of underlying processing skills and many of these skills are affected to varying degrees in children with speech and language disorders. An in-depth analysis of vowel errors has the potential to reveal the shared as well as specific underlying processing weaknesses in children with DLD, children with childhood apraxia of speech (CAS) and children with speech sound disorder (SSD). What this paper adds to existing knowledge We found that children with DLD and children with CAS show low vowel competence compared to children with typical development. A nuanced examination of vowel error types further revealed that children with DLD and children with CAS show weaknesses in encoding and memory. Motor planning and programming weaknesses were unique to CAS. Children with SSD show more mild processing deficits and their performance did not significantly differ from any of the other three groups. What are the clinical implications of this work? Examining the types of vowel errors produced by children with DLD, children with CAS and children with SSD in NWR allows us to further specify the underlying processing weaknesses that differentiate these three groups. This research informs theoretical accounts of language processing in children with different types of speech and language disorders and has the potential to improve the diagnostic utility of NWR tasks.

Nonword Repetition in Children With Developmental Language Disorder: Revisiting the Case of Cantonese.

Nonword repetition (NWR) has been described as a clinical marker of developmental language disorder (DLD), as NWR tasks consistently discriminate between DLD and typical development (TD) cross-linguistically, with Cantonese as the only reported exception. This study reexamines whether NWR is able to generate TD/DLD group differences in Cantonese-speaking children by reporting on a novel set of NWR stimuli that take into account factors known to affect NWR performance and group differentiation, including lexicality, sublexicality, length, and syllable complexity. Sixteen Cantonese-speaking children with DLD and 16 age-matched children with TD repeated two sets of high-lexicality nonwords, where all constituent syllables are morphemic in Cantonese but meaningless when combined, and one set of low-lexicality nonwords, where all constituent syllables are nonmorphemic. Low-lexicality nonwords were further classified on sublexicality in terms of consonant-vowel (CV) combination attestedness (whether or not CV combinations in nonword syllables occur in real Cantonese words). Children with DLD scored significantly below their peers with TD. Effect sizes showed that high-lexicality nonwords and nonword syllables with attested CV combinations offered the greatest TD/DLD group differentiation. Nonword length and syllable complexity did not affect TD/DLD group differentiation. NWR can capture TD/DLD group differences in Cantonese-speaking children. Lexicality and sublexicality effects must be considered in designing NWR stimuli for TD/DLD group differentiation. Future studies should replicate the present study on a larger sample size and a younger population as well as examine the diagnostic accuracy of this NWR test. https://doi.org/10.23641/asha.25529371.

The neural basis of nonword repetition in children with developmental speech or language disorder: An fMRI study

Developmental language disorder (DLD) and developmental speech disorder (DSD) are highly prevalent childhood conditions. An impaired ability to repeat nonsense words (“nonword repetition”), is claimed to be a robust behavioural marker for these conditions. Yet how brain function is altered during this task remains poorly understood. Previous research suggests that DLD or DSD may be associated with reduced brain activation in the inferior frontal and posterior temporal regions when compared to controls. However, this research is limited by within and between group variability in age, speech/language phenotype, and comorbidities. Here, we used functional MRI to examine brain activation during nonword repetition. As anticipated, behavioural findings confirmed that the DLD and DSD groups had poorer nonword repetition performance compared to typical controls. In contrast, fMRI revealed no statistically significant differences in brain activation, despite the groups appearing to engage slightly different regions when compared at identical thresholds. Therefore, whilst nonword repetition is a sensitive clinical marker for DLD and DSD, the findings from this study suggest that this task is not a sensitive brain MRI marker for children with these disorders, unlike for individuals with single gene mutations like FOXP2 mutations.

Consonant age of acquisition effects are robust in children's nonword repetition performance

ABSTRACTThe underlying processes of nonword repetition (NWR) have been studied extensively in both typical and atypical development. Most of the research examining long-term memory effects on NWR has focused on lexical and sublexical variables that can only be computed relative to the lexicon of a specific language (e.g., phonotactic probability). Sublexical variables that can be defined without reference to the lexicon (e.g., consonant age of acquisition; CAoA) have received little attention, although recent work has shown a CAoA effect on NWR in young adults by measuring performance differences when the stimuli comprise consonants acquired later versus earlier in speech development. The purpose of this study was to identify whether this sublexical effect occurs earlier in development. Thirty-one typically developing first and second graders completed NWR, nonword reading, and auditory lexical decision tasks. Nonword accuracy and word–nonword discriminability were consistently lower for items comprising later versus earlier acquired phonemes, even after controlling for vocabulary knowledge, but there were no differences in speed measures. Patterns of performance were similar to the CAoA effects observed in young adults from previous work. Results indicate that the sensitivity of NWR performance to these sublexical long-term memory effects occurs in childhood and reflects adultlike patterns of performance.

Impact of Diglossia on Word and Non-word Repetition among Language Impaired and Typically Developing Arabic Native Speaking Children.

The study tested the impact of the phonological and lexical distance between a dialect of Palestinian Arabic spoken in the north of Israel (SpA) and Modern Standard Arabic (StA or MSA) on word and non-word repetition in children with specific language impairment (SLI) and in typically developing (TD) age-matched controls. Fifty kindergarten children (25 SLI, 25 TD; mean age 5;5) and fifty first grade children (25 SLI, 25 TD; mean age 6:11) were tested with a repetition task for 1–4 syllable long real words and pseudo words; Items varied systematically in whether each encoded a novel StA phoneme or not, namely a phoneme that is only used in StA but not in the spoken dialect targeted. Real words also varied in whether they were lexically novel, meaning whether the word is used only in StA, but not in SpA. SLI children were found to significantly underperform TD children on all repetition tasks indicating a general phonological memory deficit. More interesting for the current investigation is the observed strong and consistent effect of phonological novelty on word and non-word repetition in SLI and TD children, with a stronger effect observed in SLI. In contrast with phonological novelty, the effect of lexical novelty on word repetition was limited and it did not interact with group. The results are argued to reflect the role of linguistic distance in phonological memory for novel linguistic units in Arabic SLI and, hence, to support a specific Linguistic Distance Hypothesis of SLI in a diglossic setting. The implications of the findings for assessment, diagnosis and intervention with Arabic speaking children with SLI are discussed.

The impact of attentional allocation capacities on nonword repetition in children with specific language impairment

This study aimed at directly assessing the hypothesis that attentional allocation capacity influences poor nonword repetition (NWR) performances in children with specific language impairment (SLI), using an attention demanding visual search task given concurrently with the NWR task. Twenty-one children with SLI, 21 typically developing children matched on age and 21 typically developing children matched on nonword span performed an immediate serial recall task of nonwords. The nonword lists were presented either alone or concurrently with the visual search task. Overall, results revealed a resource-sharing trade-off between the two tasks. Children with SLI were affected to the same extent as their span-matched controls by the necessity to allocate their attentional resources between the two tasks. Interestingly, nonword processing strategies seemed to differ among groups: age-matched controls allocated a larger part of their attentional resources to the encoding stage, whereas nonword recall was more attention demanding in children with SLI and younger controls.

Word recognition and nonword repetition in children with language disorders: the effects of neighborhood density, lexical frequency, and phonotactic probability.

The effects of neighborhood density (ND) and lexical frequency on word recognition and the effects of phonotactic probability (PP) on nonword repetition (NWR) were examined to gain insight into processing at the lexical and sublexical levels in typically developing (TD) children and children with developmental language problems. Tasks measuring NWR and word recognition were administered to 5 groups of children: 2 groups of TD children (5 and 8 years old), children with specific language impairment (SLI), children with reading impairment (RI), and children with SLI+RI (all 7-8 years old). High ND had a negative effect on word recognition in the older TD children and in the children with RI only. There was no ND effect in the younger children or in the children with SLI, who all had lower receptive vocabulary scores than the age-matched TD children and the RI groups. For all groups, NWR items with low PP were more difficult to repeat than items with high PP. This effect was especially pronounced in children with RI. Both the stage of vocabulary development and the type of language impairment (SLI or RI) impact the way ND and PP affect word recognition and NWR.

Nonword repetition in children with cochlear implants: a potential clinical marker of poor language acquisition.

Cochlear implants (CIs) can facilitate the acquisition of spoken language for deaf children, but challenges remain. Language skills dependent on phonological sensitivity are most at risk for these children, so having an effective way to diagnose problems at this level would be of value for school speech-language pathologists. The goal of this study was to assess whether a nonword repetition (NWR) task could serve that purpose. Participants were 104 second graders: 49 with normal hearing (NH) and 55 with CIs. In addition to NWR, children were tested on 10 measures involving phonological awareness and processing, serial recall of words, vocabulary, reading, and grammar. Children with CIs performed more poorly than children with NH on NWR, and sensitivity to phonological structure alone explained that performance for children in both groups. For children with CIs, 2 audiological factors positively influenced outcomes on NWR: being identified with hearing loss at a younger age and having experience with wearing a hearing aid on the unimplanted ear at the time of receiving a 1st CI. NWR scores were better able to rule out than to rule in such language deficits. Well-designed NWR tasks could have clinical utility in assessments of language acquisition for school-age children with CIs.

The role of phonological structure and experience in bilingual children's nonword repetition performance.

The current study examined the influence of phonological structure and language experience on the nonword repetition performance of bilingual children. Twenty-six Spanish-dominant and 26 English-dominant Spanish-English bilingual five-year-old children were matched on current exposure to the dominant language and year of first exposure to English. Participants repeated non-wordlike nonwords in English and Spanish. The Spanish-dominant group performed better than the English-dominant group for both Spanish and English nonwords. In addition, there was a main effect for test language, where Spanish nonwords were produced more accurately than English nonwords overall. The Spanish-dominant group advantage for nonwords is interpreted as emerging from the extra practice the dominant Spanish speakers had producing multisyllabic words.

Articulating Novel Words: Children's Oromotor Skills Predict Nonword Repetition Abilities

Pronouncing a novel word for the first time requires the transformation of a newly encoded speech signal into a series of coordinated, exquisitely timed oromotor movements. Individual differences in children's ability to repeat novel nonwords are associated with vocabulary development and later literacy. Nonword repetition (NWR) is often used to test clinical populations. While phonological/auditory memory contributions to learning and pronouncing nonwords have been extensively studied, much less is known about the contribution of children's oromotor skills to this process. Two independent cohorts of children (7-13 years [N = 40] and 6.9-7.7 years [N = 37]) were tested on a battery of linguistic and nonlinguistic tests, including NWR and oromotor tasks. In both cohorts, individual differences in oromotor control were a significant contributor to NWR abilities; moreover, in an omnibus analysis including experimental and standardized tasks, oromotor control predicted the most unique variance in NWR. Results indicate that nonlinguistic oromotor skills contribute to children's NWR ability and suggest that important aspects of language learning and consequent language deficits may be rooted in the ability to perform complex sensorimotor transformations.

Why computational models are better than verbal theories: the case of nonword repetition

Tests of nonword repetition (NWR) have often been used to examine children's phonological knowledge and word learning abilities. However, theories of NWR primarily explain performance either in terms of phonological working memory or long-term knowledge, with little consideration of how these processes interact. One theoretical account that focuses specifically on the interaction between short-term and long-term memory is the chunking hypothesis. Chunking occurs because of repeated exposure to meaningful stimulus items, resulting in the items becoming grouped (or chunked); once chunked, the items can be represented in short-term memory using one chunk rather than one chunk per item. We tested several predictions of the chunking hypothesis by presenting 5-6-year-old children with three tests of NWR that were either high, medium, or low in wordlikeness. The results did not show strong support for the chunking hypothesis, suggesting that chunking fails to fully explain children's NWR behavior. However, simulations using a computational implementation of chunking (namely CLASSIC, or Chunking Lexical And Sub-lexical Sequences In Children) show that, when the linguistic input to 5-6-year-old children is estimated in a reasonable way, the children's data are matched across all three NWR tests. These results have three implications for the field: (a) a chunking account can explain key NWR phenomena in 5-6-year-old children; (b) tests of chunking accounts require a detailed specification both of the chunking mechanism itself and of the input on which the chunking mechanism operates; and (c) verbal theories emphasizing the role of long-term knowledge (such as chunking) are not precise enough to make detailed predictions about experimental data, but computational implementations of the theories can bridge the gap.

Children's Nonword Repetition Tasks and English Language Learners

Nonword repetition performance has been shown to differentiate monolingual English-speaking children with language impairment (LI) from typically developing children. These tasks have been administered to monolingual speakers of different languages and to simultaneous and sequential bilingual English Language Learners (ELLs) with mixed results. This article includes a review of the nonword repetition performance of monolingual and bilingual speakers and of internationally adopted children. Clinical implications for administration and interpretation of nonword repetition task outcomes are included.

The influence of lexical status and neighborhood density on children's nonword repetition

ABSTRACTThis study examined effects of lexical status and neighborhood density of constituent syllables on children's nonword repetition and interactions with nonword length. Lexical status of the target syllable impacted repetition accuracy for the longest nonwords. In addition, children made more errors that changed a nonword syllable to a word syllable than the reverse. Syllables from dense versus sparse neighborhoods were repeated more accurately in three- and four-syllable nonwords, but there was no effect of density for two-syllable nonwords. The effect of neighborhood density was greater for a low versus high vocabulary group. Finally, children's error responses were from more dense neighborhoods than the target syllables. The results are congruent with models of nonword repetition that emphasize the influence of long-term lexical knowledge on children's performance.

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.

Real‐word repetition as a predictor of grammatical competence in Italian children with typical language development

Non-word repetition in children is a skill related to, but separable from grammatical ability. Lexical skill may bridge the gap between these two abilities. The main aim was to determine whether real-word-repetition tasks could be better as predictors of grammatical ability than non-word-repetition tasks in children with typical language. This proposal was pursued because lexical knowledge was assumed to make performance in repetition tasks more representative of other language abilities, whereas non-word-repetition tasks are heavily influenced by phonological short-term memory. In order to investigate this possibility, three repetition tasks (two real-word lists characterized by different lexical knowledge and one non-word list), were compared in three groups of three- to four-year-olds with typical language (42 children). Grammatical ability was tested through probes for third-person plural inflection and direct-object critic use. Real words were repeated more accurately than non-words and the non-words were more sensitive to Syllable length than real words. Performance on all repetition tasks was correlated with grammatical ability, but real words predicted variance in grammatical ability to a greater extent than non-words. Given the lexical information contained in real words, repetition of such words was a better predictor of grammatical ability than non-word repetition. Future research should replicate and extend these results. Tasks using real words may also have considerable clinical potential; for this reason, these tasks might also be included in studies of children with language impairment.

Computer Simulations of Developmental Change: The Contributions of Working Memory Capacity and Long‐Term Knowledge

Increasing working memory (WM) capacity is often cited as a major influence on children's development and yet WM capacity is difficult to examine independently of long-term knowledge. A computational model of children's nonword repetition (NWR) performance is presented that independently manipulates long-term knowledge and WM capacity to determine the relative contributions of each in explaining the developmental data. The simulations show that (a) both mechanisms independently cause the same overall developmental changes in NWR performance, (b) increase in long-term knowledge provides the better fit to the child data, and (c) varying both long-term knowledge and WM capacity adds no significant gains over varying long-term knowledge alone. Given that increases in long-term knowledge must occur during development, the results indicate that increases in WM capacity may not be required to explain developmental differences. An increase in WM capacity should only be cited as a mechanism of developmental change when there are clear empirical reasons for doing so.

Phonological working memory in Spanish–English bilingual children with and without specific language impairment

We examined the performance of sequential bilingual children with and without Specific Language Impairment (SLI), who had Spanish as an L1 and English as their L2, on an auditory non-word repetition task using Spanish phonotactic patterns. We also analyzed the accuracy with which this task distinguished these children (according to children's and mothers’ performance). Eleven Hispanic children with SLI ( M = 8;10), 11 age-matched children with Typical Language Development (TLD, M = 9;1), and 12 mothers, participated. They were living in New York City. The participants’ repetition of 20 non-words (four at each of five syllable lengths) was scored for item and segmental accuracy, and error type. We examined the relations among children's non-word repetition performance, language scores, and, for a subset of the children, their mothers’ non-word repetition performance. The percentage of correct non-words was significantly lower in children with SLI than in children with TLD. A length effect was found in 3–4–5 syllable non-words. Consonant substitutions and consonant omissions were significantly higher in children with SLI than with TLD. Both groups showed a similar relative pattern of more consonant than vowel errors. The children's non-word repetition performance correlated strongly with three of the four Spanish ITPA subtests we administered. The mothers of children with SLI performed more poorly than the mothers of the children with TLD, for the 20 non-words and the subset of 3–4–5 syllable non-words. Non-word repetition performance is an accurate identifier of language status in these groups (likelihood ratios are reported). The potential clinical application of this task in identifying SLI in bilingual Spanish-speaking children (on the basis of children's and mothers’ performance) is discussed. Learning outcomes: In the future, with a set of norms, this task could be used as a screening test to help detecting children with SLI or at risk for SLI.

Non‐word repetition in Spanish‐speaking children with Specific Language Impairment (SLI)

A number of previous studies have revealed that children with Specific Language Impairment have limitations in Phonological Working Memory as revealed by a task that requires them to repeat non-words of increasing syllable length. However, most published studies have used non-words that are phonotactically English. The purpose was to examine the repetition of non-words that are consistent with the phonotactic patterns of Spanish. The study also examined the relationship between non-word repetition performance and other language measures. Eleven Spanish-speaking children with Specific Language Impairment and 11 age-matched children with typical language development aged 8;3-10;11, who were part of a larger study of sentence processing, participated in the study. The primary data were the children's repetition of 20 non-words, four at each syllable length (one, two, three, four and five syllables). The children's productions were transcribed and scored for non-word, segmental and cluster accuracy as well as for error type. The children with Specific Language Impairment performed more poorly on almost all measures of accuracy, but particularly in their production of three-, four-, and five-syllable non-words. Substitutions were the most frequent error type for both groups. Likelihood ratios indicated that non-word repetition performance is a highly accurate identifier of language status in these preselected groups. The children's non-word repetition was highly correlated with most of the standardized language measures that were administered to the children. The repetition of non-words consistent with Spanish phonotactics reveals word-length effects and error patterns similar to those found in previous studies. It extends these findings to older school-age Spanish-speaking children with Specific Language Impairment. Given the limited choices for instruments that can be used to identify children with Specific Language Impairment, a Spanish Non-word Repetition Task has the potential to be a valuable screening test for clinical and research purposes.

Non-Word Repetition in Children with Specific Language Impairment: A Deficit in Phonological Working Memory or in Long-Term Verbal Knowledge?

In this study we investigated the effects of long-term memory (LTM) verbal knowledge on short-term memory (STM) verbal recall in a sample of Italian children affected by different subtypes of specific language impairment (SLI). The aim of the study was to evaluate if phonological working memory (PWM) abilities of SLI children can be supported by LTM linguistic representations and if PWM performances can be differently affected in the various subtypes of SLI. We tested a sample of 54 children affected by Mixed Receptive-Expressive (RE), Expressive (Ex) and Phonological (Ph) SLI (DSM-IV - American Psychiatric Association, 1994) by means of a repetition task of words (W) and non-words (NW) differing in morphemic structure [morphological non-words (MNW), consisting of combinations of roots and affixes - and simple non-words - with no morphological constituency]. We evaluated the effects of lexical and morpho-lexical LTM representations on STM recall by comparing the repetition accuracy across the three types of stimuli. Results indicated that although SLI children, as a group, showed lower repetition scores than controls, their performance was affected similarly to controls by the type of stimulus and the experimental manipulation of the non-words (better repetition of W than MNW and NW, and of MNW than NW), confirming the recourse to LTM verbal representations to support STM recall. The influence of LTM verbal knowledge on STM recall in SLI improved with age and did not differ among the three types of SLI. However, the three types of SLI differed in the accuracy of their repetition performances (PMW abilities), with the Phonological group showing the best scores. The implications for SLI theory and practice are discussed.

Beyond words: Phonological short-term memory and syntactic impairment in specific language impairment

The assessment of nonword repetition in children goes back at least to 1974, when the Goldman–Fristoe–Woodcock Auditory Skills Battery was published, including a subtest (Sound Mimicry) assessing nonword repetition (Goldman, Fristoe, & Woodcock, 1974). Nevertheless, it was not until 20 years later, when Gathercole and Baddeley (1990) reported a study of short-term memory in children with specific language impairment (SLI), that a theoretical framework was developed linking deficits in nonword repetition to impaired language acquisition. Gathercole's Keynote in this issue (2006) tells the story of how this initial study revealed a striking nonword repetition deficit in children with SLI, complementing work on typically developing children showing a major role of phonological short-term memory (STM) in word learning. As she points out, the story is a complex one: phonological STM is not the only skill tapped by the nonword repetition task, and children may do poorly for different reasons. Furthermore, relationships between nonword repetition and word learning may be reciprocal, with vocabulary level affecting children's ability to segment nonwords efficiently and retain them in memory. However, the original finding, that deficient nonword repetition is a strong correlate of SLI, has stood the test of time, to the extent that poor performance on this test has been used successfully as a marker of a heritable phenotype in molecular genetic studies of SLI (Newbury, Monaco, & Bishop, 2005).