spanish & english nwr

Research Report

Bilingual performance on nonword repetition in Spanish and English

Connie Summers†, Thomas M. Bohman‡, Ronald B. Gillam§, Elizabeth D. Pena† and Lisa M. Bedore†

†Communication Sciences and Disorders, University of Texas at Austin, Austin, TX, USA‡Center for Social Work Research, School of Social Work, University of Texas at Austin, Austin, TX, USA§Utah State University, Logan, UT, USA

(Received November 2008; accepted July 2009)

Abstract

Background: Nonword repetition (NWR) involves the ability to perceive, store, recall and reproduce phonologicalsequences. These same abilities play a role in word and morpheme learning. Cross-linguistic studies of performanceon NWR tasks, word learning, and morpheme learning yield patterns of increased performance on all three tasks as afunction of age and language experience. These results are consistent with the idea that there may be universalinformation-processing mechanisms supporting language learning. Because bilingual children’s language experienceis divided across two languages, studying performance in two languages on NWR could inform one’s understandingof the relationship between information processing and language learning.Aims: The primary aims of this study were to compare bilingual language learners’ recall of Spanish-like and English-likeitems on NWR tasks and to assess the relationships between performance on NWR, semantics, and morphology tasks.Methods&Procedures:Sixty-two Hispanic children exposed to English and Spanish were recruited from schools in centralTexas, USA. Their parents reported on the children’s input and output in both languages. The children completed NWRtasks and short tests of semantics and morphosyntax in both languages. Mixed-model analysis of variance was used toexplore direct effects and interactions between the variables of nonword length, language experience, language outcomemeasures, and cumulative exposure on NWR performance.Outcomes & Results: Children produced the Spanish-like nonwords more accurately than the English-like nonwords.NWR performance was significantly correlated to cumulative language experience in both English and Spanish. Therewere also significant correlations between NWR and morphosyntax but not semantics.Conclusions & Implications: Language knowledge appears to play a role in the task of NWR. The relationship betweenperformance on morphosyntax and NWR tasks indicates children rely on similar language-learning mechanisms tomediate these tasks. More exposure to Spanish may increase abilities to repeat longer nonwords. This knowledge mayshift across levels of bilingualism. Further research is needed to understand this relationship, as it is likely to haveimplications for language teaching or intervention for children with language impairments.

Keywords: nonword repetition, bilingual, Spanish.

What this paper addsWhat is already known on this subjectThe ability to repeat nonwords increases with age and language experience across languages. This relationship holdsfor bilingual children as well, but in several studies bilingual performance falls below monolingual performance.Most studies with bilingual children have used only nonwords based on one language. This study explores nonwordrepetition and language performance in English and Spanish with children who have been exposed to bothlanguages.

What this study addsChildren’s performance varied as a function of language exposure across languages, but they demonstrated higheraccuracy in their production of Spanish nonwords. Semantics and morphosyntax have different relationships withnonword repetition in children with varying language experiences.

International Journal of Language & Communication DisordersISSN 1368-2822 print/ISSN 1460-6984 online q 2010 Royal College of Speech & Language Therapists

http://www.informahealthcare.com

DOI: 10.3109/13682820903198058

Address correspondence to: Connie Summers, Communication Sciences and Disorders, The University of Texas at Austin, 1 University StationA1100, Austin, TX 78712, USA; e-mail: [email protected]

INT. J. LANG. COMM. DIS., JULY–AUGUST 2010,VOL. 45, NO. 4, 480–493

Introduction

Nonword repetition (NWR) is often used to investigatethe phonological short-term memory mechanismsunderlying language learning in children. In this task,children repeat increasingly longer nonwords com-prised of syllables that conform to the phonotacticconstraints of the target language (for an in-depthdiscussion of item development, see Gathercole andBaddeley 1989, and Gathercole et al. 1992). Immediaterecall of unmeaningful phonological sequences dependsheavily on children’s ability to perceive, store, recall, andreproduce accurately strings of phonological sequences(Baddeley 2003). NWR is of special interest toresearchers who study language development anddisorders because the skills necessary to repeat non-words play an important role in learning new words andmorphemes. Numerous studies show that performanceon NWR tasks predicts vocabulary development(Adams and Gathercole 1995, Roy and Chiat 2004)and, to a lesser degree, syntactic development (Graf Esteset al. 2007, Sahlen et al. 1999).

Nonword difficulty increases as a function ofnon-word length in syllables, across a number oflanguages including Italian (Bortolini et al. 2006,D’Odorico et al. 2007), Spanish (Girbau and Schwartz2007), Swedish (Radeborg et al. 2006, Reuterskiold-Wagner et al. 2005), Dutch (Gijsel et al. 2006), Greek(Masoura and Gathercole 2005), French (Klein et al.2006), Portuguese (Santos et al. 2006), and Cantonese(Stokes et al. 2006). In these studies children’s ability torepeat nonwords accurately increases with age andvocabulary size. These results suggest that the skillsrequired to repeat nonwords are universal and maysupport language learning.

Underlying mechanisms in NWR

The underlying mechanisms employed to repeat non-words include phonological processing (Bowey 1996,1997), articulation skills, speech perception (Frisch et al.2000), and phonological short-term memory(Gathercole et al. 1992, Masoura and Gathercole 2005,Gathercole 2006). Baddeley’s (2003) model of workingmemory provides a useful framework for thinking aboutthe phonological short-term memory mechanisms thatcontribute to NWR. The most recent model includesthree important components of fluid memory. Two slavesystems, the phonological loop and the visual-spatialsketchpad, are controlled by a central executive. Thephonological loop holds auditory information for a briefperiod of time and includes a method of rehearsal to retainthat information for longer periods. The central executivecontrols the use of the slave components throughattention and inhibition. This model of working memory

also includes crystallized memory systems that store long-term information including language knowledge. Thephonological loop interacts with long-term languageknowledge in a reciprocal relationship. Repeating non-words uses both of these. In the phonological loop orphonological working memory, sound segments are heldand rehearsed to facilitate repetition. Long-term languageknowledge is activated when sound segments resemblelexical representations. Phonotactic rules of a languagemay additionally mediate the repetition of nonwordsbecause retention and recall processes rely, in part, onrapid activation of well-specified phonotactic knowledge.

Children who are actively engaged in learning twolanguages might develop particularly strong phonolo-gical representation, storage, and retrieval systems as aby-product of requirements for bilingual languagelearning and use (Bialystok et al. 2003). On the otherhand, because input in each language is necessarilydistributed across their languages, they may developrelatively weaker representations in both their languages(Gollan et al. 1997). It is also possible that bilinguallanguage development results in unique relationshipsbetween the cognitive processes underlying languagelearning (such as phonological short-term memory) andlevels of language knowledge. This study was designedto explore the relationships between language experi-ence and phonological memory skills and languageknowledge in children with varying languageexperiences.

Role of experience in nonword repetition

The degree to which NWR interacts with long-termlanguage knowledge is a function of the word-likeness ofthe nonwords (Dollaghan et al. 1995) and the extent towhich they conform to the phonotactic rules of thetarget language (Archibald and Gathercole 2006,Gathercole et al. 1999). Word-likeness and phonotacticprobability are related because words with highphonotactic probability are judged to be more word-like (Frisch et al. 2000). High probability nonwordsare repeated more accurately than low probability non-words demonstrating the role of frequency in NWR taskperformance. But this frequency effect is usually largerfor children with smaller vocabularies and for childrenwith language impairment (Munson et al. 2005). Forexample, high-word-like (i.e., perplisteronk and glister-ing) and/or high-probability phoneme sequences withinnonwords might invite a greater role for prior languageknowledge in a NWR task. In contrast, low-word-likenonwords (i.e., teivak and naib) and nonwordscontaining low-probability phoneme sequences soundless like real words and invite a lesser role for priorlanguage knowledge. Thus, children’s language knowl-edge and experience with language(s) can influence their

Nonword repetition 481

performance on this seemingly non-linguistic task(Edwards et al. 2004, Munson et al. 2005, Frisch et al.2000).

Phonotactic properties of English and Spanish

Performance on NWR tasks seems to be influenced bythe specific phonological and phonotactic structure ofthe particular language a child is learning. Spanish andEnglish, for example, differ in the number of soundsavailable to produce contrasting phonotactic structures.Standard American Spanish uses five vowels and 20consonants but English uses 13 vowels and 24consonants (Hammond 2001). Thus, at the phonolo-gical level there are more possibilities for contrastingsound combinations in English than in Spanish.Furthermore, the child’s language environment pro-vides examples of the word-shapes and phonologicalpatterns of that language in varying degrees. Phono-tactic rules govern the possible number of syllables,consonant clusters, stress patterns, and phonemesequences, and these rules influence the likelyarrangement of phonemes in words. As summarizedin Table 1, Spanish has more multi-syllable words thandoes English (Shriberg and Kent 1982, Navarro 1968).

These phonological and phonotactic differences inSpanish and English influence rate of acquisition of thesound system in each language. Children learningSpanish master the sounds of the language relativelyearlier than do children learning English. In English,fricatives, affricates, liquids, and velars are laterdeveloping sounds and are mastered between ages4 and 5 years (Porter and Hodson 2001). In contrast,children learning Spanish produce most Spanishconsonants and sound combinations accurately by age4 (Goldstein and Iglesias 1996). These differences maybe attributed to the number of sounds to be learned andthe possible contrasts to be produced. English gainsphonotactic complexity by adding syllable finalconsonants and consonant sequences. Spanish gainsphonotactic complexity by adding syllables andconsonant vowel sequences.

Differences in the phontactic rules of the Englishand Spanish languages affect NWR performance.For example, children learning languages in whichmulti-syllable words are frequent such as Portuguese

(Santos and Bueno 2003) and Greek (Masoura andGathercole 1999) appear to be better at producinglonger nonwords (up to five- and six-syllable non-words, respectively). Because longer words are morefrequent in Spanish than English, we would expect thatchildren exposed to Spanish would be able to producelonger nonwords.

Morphosyntactic influences

Morphosyntactic structure may also mediate linguistictasks and influence performance on NWR acrosslanguages. Vitevitch and Stamer (2006) found that incontrast to English, Spanish words from sparseneighbourhoods (i.e., words with few similar soundingwords) are produced more quickly than Spanish wordsfrom dense neighbourhoods (i.e., words with manysimilar sounding words). This result contrasts withfindings in studies of English that words from denseneighbourhoods were named more quickly than wordsfrom sparse neighbourhoods (Gordon and Dell 2001,Vitevitch 2002). Vitevitch and Stamer hypothesizedthat the opposing patterns in English and Spanish wordproduction rates might be the result of inherentdifferences between the two languages. Because Spanishis highly inflected in contrast to English, similarSpanish words (e.g., bonita and bonito) may competemore due to their phonological and semantic similaritythan words in English (e.g., cat and can) which arephonologically, but not semantically similar.

Vocabulary exposure

Most studies of the relationship between NWR andlanguage focus on vocabulary, although there are somestudies that explore NWR and other language domains.The relationship between NWR and vocabularylearning appears to be mediated by language learningexperience as indexed by age. Adams and Gathercole(1995) observed weak-to-moderate correlationsbetween NWR and performance on the British PictureVocabulary Scale (Dunn and Dunn 1982) of 0.21–0.42for younger and older 3-year-olds, respectively. This issimilar to the correlation between receptive vocabularyand NWR (0.42) reported by Roy and Chiat (2004) forchildren ranging from 2 to 4 years of age. Highercorrelations between NWR and receptive vocabularywere found for children between the ages of 4 (0.56), 5(0.52), and 6 (0.56) years (Gathercole et al. 1992). Byage 8 the correlation between the two tasks was reportedto be 0.28. These findings suggest that phonologicalworking memory plays a larger role in the vocabularylearning process when children have less knowledge.But, the demands on phonological working memory

Table 1. Word frequencies in English and Spanish

One-syllablewords

Two-syllablewords

Three-syllablewords

Four-syllablewords

Five-syllablewords

English 76.92 17.05 4.55 n.a. n.a.Spanish 7.54 25.83 19.67 6.87 1.42

Note: n.a., Not available.

482 Connie Summers et al.

may diminish once children have a larger linguistic baseand more practice with vocabulary learning.

Similar patterns of language knowledge and NWRaccuracy have been observed for second languagelearners. For 10-year-old Greek-speaking children, thecorrelation between Greek NWR and receptivevocabulary was lower (0.33) than the relationship forEnglish nonwords and second language vocabulary(0.66) (Masoura and Gathercole 2005). In a study of7th-grade Cantonese speakers learning English,Cheung (1996) found that the relationship betweenNWR and vocabulary in English held for those whoseEnglish vocabulary size was below the group mean.

Language experiences

The languages children are exposed to and theirvarying proficiency in multiple languages mayinfluence their NWR performance. Evidence for thiscomes from three studies. In one study, Masoura andGathercole (1999) found that Greek children learningEnglish as a second language were more accuraterepeating nonwords in their native language (Greek)than in the second language (English) in two- to five-syllable nonwords. Performance on NWR wasmediated by language experiences. In this case,Greek, the language with the most experience andproficiency was the most accurate. In contrast, thechildren had less exposure to and were less proficientin English resulting in lower NWR scores. Likewise,Thorn and Gathercole (1999) found that Englishmonolinguals scored lower on French nonwordscompared to the simultaneous French–Englishbilingual children who scored similarly in bothlanguages. The patterns of age and languagecontributions to the nonword scores differed bylanguage. While age and vocabulary knowledgecontributed a total of 20% of the variance in theEnglish nonword scores, 38% of the French non-word scores were accounted for by vocabularyknowledge alone without contribution by age.Similarly, Kohnert et al. (2006) compared perform-ance on a NWR task in three groups of children:typical Spanish–English sequential bilinguals, typicalmonolingual English speakers, and monolingualEnglish speakers with specific language impairments(SLI). The bilingual Spanish –English childrenproduced English-like nonwords less accurately thantypically achieving monolingual English children butmore accurately than English only children with SLI.It may be that respective English proficiency impactedthe bilingual children’s ability to repeat nonwords.Also, using English nonwords only did not fullyportray the bilinguals children’s NWR skills.

Nonword repetition and other language measures

Some studies have examined the relationship betweenperformance on NWR measures and other languagemeasures. Ebert et al. (2008) did not find a relationshipbetween Spanish NWR and the Preschool LanguageScales (Zimmerman et al. 2002a, 2002b) in English orSpanish. Yet, measures of morphosyntax knowledgehave been related to NWR. Adams and Gathercole(1995) explored the relationship between NWR andgrammatical complexity as indexed by mean length ofutterance–morphemes (MLU-m), type-token ratio(TTR), and the Index of Productive Syntax (IPSyn)(Scarborough 1990). A significant correlation (0.364)between NWR and the total IPSyn was found forchildren between 34 and 37 months old. Follow-uptesting 7 months later indicated a significant correlationonly between initial IPSyn Noun Phrase subscore andNWR, not the total IPSyn. The authors proposed thatthis relationship was indicative of the role of short-termphonological memory in learning and then storinggrammatical forms. Indeed, children with specificlanguage impairment, whose language is characterizedby difficulty in morphology and syntax, also havedifficulty on NWR tasks (Graf Estes et al. 2007).In Swedish speakers, NWR performance was correlatedto both phonology (0.61) and expressive grammar(0.41) (plural forms, genitives, propositions, negationand verb tense) as measured on a test of grammaticalproduction (Sahlen et al. 1999).

Tasks that are less directly related to the lexicon andmorphosyntax demonstrate how NWR might berelated to language learning more broadly. In a studyof Spanish speaking school-age children (8–10 yearsold) NWR was moderately correlated to grammaticalintegration (Girbau and Schwartz 2007). For childrenlearning Greek and English, NWR performancecorrelated with their ability to perform translationtasks (Masoura and Gathercole 2005). These findingsindicate that the role of phonological working memoryextends beyond initial learning of words and syntacticforms to meta-awareness of language.

Developmental and relational similarities betweenperformance on NWR tasks and language ability acrossmultiple languages indicate that phonological workingmemory has strong universal characteristics. However,there are also language specific influences. At the level ofsyntax, Marton et al. (2006) observed cross-linguisticdifferences in NWR performance when children wereasked to recall nonwords in short sentences with simpleversus morphologically or syntactically complex con-structions. Hungarian-speaking children recalled non-words in simple and short complex sentences.Performance was affected more by morphologicalcomplexity. English speakers on the other hand were


affected more by syntactic complexity. This demon-strates that performance on NWR tasks is influenced bythe particular language a person knows. In addition, therelationship between NWR performance and languagedepends on the aspect of language under study and thecharacteristics of that language.

Studying NWR performance in bilingual childrenprovides a way to explore the role of languageproficiency, usage and experience on phonologicalshort-term memory. Because bilinguals learn twophonotactic systems, two lexical, and two syntacticsystems, demands on their short-term memory andattentional systems may be different. Language learningin bilingual children is not equally divided across twolanguages. Varying levels of fluency and proficiencymay have different relationships to NWR. Here, wewere interested in exploring the effects of languageknowledge on children’s abilities to represent, store,and produce nonwords, specifically:

. What are the patterns of NWR performance inchildren with varying experience in Spanish andEnglish?

. What is the relationship between phonologicalshort-term memory (as assessed by NWR) andperformance on semantic and morphosyntaxlanguage tasks?

Methods

Participants

Sixty-two children between the ages of 4;6 and 6;5participated in the study. Parents identified theirchildren as Hispanic in a parent interview. Forty-fourparents rated their Spanish as Mexican, two asVenezuelan, and one each as Puerto Rican, Honduran,Cuban, and pure Spanish. The type of Spanish spokenat home was unavailable for ten children. Two childrenwere excluded from analyses due to their participationin a larger study. All children passed a hearingscreening. We report on data of 60 children from theoriginal 62 children tested. Fifty-four children weretested in both English and Spanish, one child was onlytested in Spanish, and five children were tested inEnglish only. The six children who were only tested inone language were unavailable for testing in the secondlanguage.

Parents completed questionnaires in which theyreported on their children’s hour-by-hour exposure to(input) and use (output) of Spanish and English. Theywere also asked what language their child was exposedto at home and at school during each year of their life.From this information, the first year of Englishexposure was determined for each child.

Measures

Three measures, a NWR task, a semantic task and amorphosyntax task were administered in both Englishand Spanish. To the extent possible, we wanted toequate the influence of semantic knowledge on theperformance on the NWR tasks across the children withdiffering patterns of experience with Spanish andEnglish. Therefore, the NWR tasks were comprised ofa set of low-word-like nonwords for each language.The items from the English NWR task were developedby Dollaghan and Campbell (1998). The Spanish non-words were developed by Calderon (2003). The Englishlist included twelve nonwords (four nonwords sets oftwo, three, and four syllables). The Spanish listconsisted of 17 nonwords ranging from two- to four-syllables (four two-syllable, five three-syllable, and threefour-syllable words). We report the percent of correctphonemes within each syllable length to control for thedifferent numbers of nonwords in each language.

Both nonword lists followed the phonotacticconstraints of each language and included only tensevowels. More specifically, Dollaghan and Campbell(1998) created their English nonwords by excludinglate developing sounds, consonant clusters, andindividual syllables that corresponded to real Englishwords, positioning consonants in the beginning andending of nonwords (and only in syllable positionswhere those consonants occur less the 25% of the time),and not using a consonant or vowel more than once in anonword. Calderon (2003) described the constraintsused in the development of the Spanish nonwords. Allsyllables occurred less than 200 times in the Alamedaand Cuetos (1995) corpus of 2 million words.Non-words did not resemble real words in English orSpanish. Few later developing sounds in Spanish wereused (i.e., /s/ and /r/). Finally, stress patterns in the non-words reflected the Spanish language, the penultimateor last syllable was stressed.

In addition, we wanted to ensure that English andSpanish nonwords were equivalent in their degree ofnonword likeness. Ten bilingual adults listened to the33 nonwords used in the study interspersed by sixadditional filler nonwords. The nonwords from bothlists were randomized and each bilingual adult listenedto each nonword once to decide if it sounded moreEnglish-like or more Spanish-like. Overall, Englishnonwords were rated to be English-like 80.5% ofthe time (standard deviation (SD) ¼ 11.5). Spanishnonwords were rated to be Spanish-like 77.1% of thetime (SD ¼ 2.02).

Both English and Spanish nonwords were digitallyrecorded by a female speaker on a Power Macintosh G3computer using the Peak 3.11 software. Nonwordswere presented on laptop computers (iBook G3,


MacBook, or Compaq). Presentation of English andSpanish nonwords was counterbalanced. Participants’responses were audiorecorded by a microphone (SonyECM-C115) clipped to a participant’s shirt andrecorded on a digital recorder (Sony ICD-P320).The digital recordings were transferred to Dell(Optiplex GX620) computers using Digital VoiceEditor 2 (version 2.4) for transcription.

The semantics measure came from the BilingualEnglish Spanish Assessment (BESA) (Pena et al. 2009).Items included associations, characteristic properties,categorization, functions, linguistic concepts, andsimilarities and differences (for an in-depth discussionof item development, see Pena et al. 2003). It isimportant to note that the semantics screener wasdeveloped to assess semantic knowledge, rather thanreceptive or expressive vocabulary. Twelve items fromthe BESA were selected for the Spanish SemanticsScreener. The English semantics screener consisted often items for 4-year-old children and eleven items for5-year-old children (eight of the items were in commonacross the two screeners). Statistical analyses comparedthe correlation between the full BESA subtest and thescreener items in each language based on normativedata for a large sample of 5-year-old children.Correlations were significant for Spanish semantics,r(172) ¼ 0.855, p , 0.001 and for English semantics,r(185) ¼ 0.887, p , 0.001. In addition, the BESAsemantics subtest and the semantics screener wereindependently administered to 20 children (15 ofwhom also participated in the current study). Resultsindicated significant positive correlations between theBESA semantics subtest and the semantics screener forSpanish, r(19) ¼ 0.696, p , 0.001 and Englishr(19) ¼ 0.639, p , 0.001.

The Morphosyntax screener was also created fromitems on the BESA. Both English and Spanishmorphosyntax screeners included cloze task items(e.g., articles, clitics, and subjunctive for Spanish; third-person singular, negation, passives, past tense, pro-gressive -ing, and copula for English) and sentencerepetition items (Gutierrez-Clellen et al. 2006). Therewere 17 items on the Spanish morphosyntax screenerand 16 items on the English morphosyntax screener.Based on normative data for 5-year-old Spanish- andEnglish-speaking children, correlations between theBESA morphosyntax subtest and the screener werestatistically significant for Spanish r(140) ¼ 0.826,p , 0.001 and English r(127) ¼ 0.893, p , 0.001.The same 20 children were administered themorphosyntax screener in both languages and theBESA morphosyntax subtest independently. Therewere large significant correlations between the BESAmorphosyntax subtest and the morphosyntax screener

for both Spanish r(19) ¼ 0.858, p , 0.001 andEnglish r ¼ 0.754, p , 0.001.

Procedures and analyses

Administration of the tasks took place at each child’sschool in a quiet room and were administered by abilingual speech language pathologist. For all tasks,instructions were provided to the child in the targetlanguage, English or Spanish. For the NWR task, theexaminer said, ‘You are going to hear some silly words.Listen carefully to each word and then tell me what youheard. Let’s practice.’ The examiner then presented twopractice items. If the participant did not respond tothe practice items, more items were given for practice.The nonwords were then presented. Every participantattempted the task.

For the Semantics screener, the examiner said,‘I’m going to show you some pictures and then ask yousome questions about my pictures.’ The items werethen presented. The Morphosyntax screener began withdemonstration items. Each target form for the clozetasks was preceded by two demonstration items of thatform. Feedback was provided to the child during thedemonstration items until they understood the task.There were also two sentence repetition examples forthat portion of the screener. Again, all instruction anddemonstration items were presented in the targetlanguage. Every child attempted both the semantics andmorphosyntax screeners.

A bilingual research assistant transcribed eachnon-word by listening to the recording throughheadphones (Labtex Elite-820) using Digital VoiceEditor 2. Each phoneme was scored as correct orincorrect. Scoring procedures followed those used byDollaghan and Campbell (1998). An incorrect scoreincluded an omission or substitution for the targetphoneme. Distortions were scored as correct. Additionswere not counted as errors. When syllables wereomitted, the remaining syllables were matched to thetarget syllables and scored for phonemes in that targetsyllable. For each syllable level, the total number ofcorrect phonemes was divided by the total number ofphonemes and reported as percent phonemes correct(PPC). PPC is an average score for a syllable level. Thisallowed us to compare performance at each syllablelevel regardless of the number of items for each level.A second bilingual research assistant independentlytranscribed and scored 11% of the samples (13 out of114). Scores were compared with the scores from thefirst research assistant on a phoneme by phonemelevel to establish scoring reliability. Scoring reliabilityfor the 13 samples ranged from 76% to 89% with anaverage of 84%.


The semantics and morphosyntax screeners wereadministered in English and Spanish by bilingualclinicians. Responses were recorded verbatim duringadministration and later scored as correct or incorrect.Item scores were then entered into an Excel spreadsheet.Percentages for each screener were calculated andentered into the spreadsheet for analysis.

Results

Descriptive results

Table 2 shows the breakdown of NWR and BESAscores by language of testing (English and Spanish) andnumber of syllables. NWR scores appear to decline asthe number of syllables increase. BESA scores are shownseparately for Morphosyntax and Semantics. Notehowever the large standard deviations for all the scores.

Analysis

To address the study’s overall goal of comparing NWRscores by children’s language experience and testlanguage, five statistical models were run using NWRscores as the dependent variable (Table 3) to test the twohypotheses separately for English and Spanish. First, amixed-model analysis of variance (ANOVA) was usedto test whether there was a direct effect of non-wordlength (number of syllables), language experience (inputand output), language outcomes (morphosyntax andsemantics), and cumulative language exposure (age andage of first English exposure). Second, four mixed-model ANOVAs tested whether NWR scores varieddepending on the joint influence of two predictors.These models tested whether the relationship betweenNWR scores and language outcomes, languageexperience, and exposure varied depending on

nonword length. In addition, the relationship betweenlanguage experiences and NWR scores was testedwhether it varied depending on exposure.

Each of the five models utilized a multilevelapproach to avoid the possibility of statisticallysignificant differences due to the decreased standarderror resulting from non-independence in participantscores within a particular person depending onlanguage (English or Spanish), or NWR word length(two, three, and four syllables) (Raudenbush and Bryk2002). The degrees of freedom for statistical signifi-cance tests were calculated using the Kenward–Rogeradjustment for degrees of freedom in mixed-models forrepeated measures, because it reduces the potential forType I error (Littel et al. 2002). A random person effectwas included to account for individual effect on eachlanguage assessed. For the NWR task within-subjecteffect, the unstructured variance–covariance matrix wasused to model the within-person, within-languagecorrelation among scores. Effect sizes are reported asstandardized regression coefficients with 95% confi-dence intervals for continuous variables and as pseudo-R 2 measures based on proportional reduction inresidual error for non-continuous variables such assyllable (Snijders and Bosker 1999). Cohen (1988)provided the following guide for interpretation ofstandardized coefficients: 0.5 is large, 0.3 is moderate,0.1 is small, and less than 0.1 is trivial. To helpunderstand the meaning of the standardized regressioncoefficients, they can be squared to get a measure ofexplained variance. For example, a coefficient of 0.2would indicate that 4% of the variance was explained; acoefficient of 0.4 would explain 16% of the varianceand so forth.

Research question: direct effects

The first research question concerned direct effects ofnumber of syllables, language experience, languageoutcomes and language exposure for the English andSpanish nonwords (see Table 4). Results are reportedseparate for English and Spanish nonwords.

English

The mixed-model analysis showed there were statisti-cally significant main effects for morphosyntaxF(1,45) ¼ 5.9, p , 0.05, and nonword lengthF(2, 50) ¼ 29.2, p , 0.001 (R 2 ¼ 0.28). A one unitincrease in Morphosyntax score was related to a 1.5%increase in percentage correct standardizedcoefficient ¼ 0.47, confidence interval (CI) ¼ 0.08–0.86. The means for the nonword length were twosyllables ¼ 70.2, three syllables ¼ 65.0, and foursyllables ¼ 50.9. The differences between two- and

Table 2. Number of participants, means and standarddeviations for nonword repetition (NWR) scores and BilingualEnglish Spanish Assessment (BESA) scores by language and

group

English Spanish

Mean SD Mean SD

NWR percentage correctTwo syllables 70.2 16.4 78.9 12.4Three syllables 66.3 15.9 69.5 13Four syllables 51.7 17.8 64.3 15.3

BESA scalesMorphosyntax 4.5 4.6 8.5 5.3Semantics 4.7 3.2 6.8 3.5

Current language experiencePercentage input 38.7 31.4 61.2 31.6Percentage output 43.9 35.4 56.3 35.2

Note: SD, standard deviation.


three-syllables with four syllables were significantlydifferent at the p , 0.05 level using Tukey–Krameradjusted multiple comparison tests.

Spanish

The mixed-model analysis showed there were statisti-cally significant main effects for morphosyntaxF(1,40) ¼ 11.8, p , 0.001, language outputF(1,40) ¼ 5.4, p , 0.05, and nonword length F(2,45) ¼ 22.5, p , 0.001 (R 2 ¼ 0.28). A one unitincrease in Morphosyntax score was related to a 1.7%increase in percentage correct (standardizedcoefficient ¼ 0.51, CI ¼ 0.08–0.86). A 1% increasein Spanish output was related to a 0.3 decrease inpercentage correct (standardized coefficient ¼ 20.59,CI ¼ 21.1 to 20.08). The means for the nonwordlength were two syllables ¼ 77.9, three syllables ¼ 68.9,

and four syllables ¼ 62.6. The differences between allthree nonword lengths were significantly different at thep , 0.05 level using Tukey–Kramer adjusted multiplecomparison tests.

Research question: interaction effects

The second research question concerned interactiveeffects of nonword length, language experience,language outcomes and language exposure for theEnglish and Spanish nonwords (see Table 5). There wasa marginally statistically significant interaction betweennonword length and morphosyntax (model 2a)F(2,48) ¼ 3.2, p ¼ 0.052 in English. There were nostatistically significant interactions for language experi-ence (model 2b) for either English or Spanishnon-words exposure and language outcomes (model2d) or language experiences (model 2b) for either

Table 3. Effects tested in each model and the corresponding research questions

Model effectModel 1:

Direct effects

Model 2a:OutcomesX syllables

Model 2b:Current experience

X syllables

Model 2c:Prior experience

X syllables

Model 2d:Prior experience

by current experience

Language output £ £ £ £Language input £ £ £ £Number of syllables £ £ £ £Age £ £ £ £First exposure to English £ £ £ £Morphosyntax £ £ £ £Semantics £ £ £ £

Language performance interactionsNumber of syllables X morphosyntax £Number of syllables X semantics £

Current language exposureNumber of syllables X input £Number of syllables X output £

Cumulative exposureNumber of syllables X age £Number of syllables X age of firstEnglish exposure

£

Cumulative exposure by current exposureAge X input £Age X output £

Table 4. Model 1: Direct effects

English Spanish

Effect Number of d.f. Den d.f. F-value Pr . F Number of d.f. Den d.f. F-value Pr . F

Nonword length 2 50 29.16 ,0.0001 2 45 22.52 ,0.0001Age 1 45 2.42 0.1270 1 40 4.06 0.0506Age at first English exposure 1 45 0.08 0.7722 1 40 1.81 0.1860Morphosyntax 1 45 5.90 0.0192 1 40 11.85 0.0014Semantics 1 45 2.10 0.1538 1 40 0.31 0.5826Input 1 45 0.16 0.6880 1 40 1.70 0.2003Output 1 45 0.05 0.8330 1 40 5.43 0.0249

Note: Number of d.f. ¼ number of groups - 1; Den d.f. ¼ n - number of groups.


English or Spanish nonwords. There were statisticallysignificant interactions between nonword length and ageof first exposure to English for both EnglishF(2,48) ¼ 6.1, p , 0.01 (R 2 ¼ 0.05) and Spanishnonwords F(2,43) ¼ 7.3, p , 0.01 (R 2 ¼ 0.08).

English

Figure 1 shows the interaction between English nonwordlength and morphosyntax. Ordinary least-squares (OLS)regressions between NWR score and morphosyntax scoreby number of syllables showed there were positiverelationships between morphosyntax and NWR percen-tage correct for two syllables (r ¼ 0.34, R 2 ¼ 0.12) andthree syllable (r ¼ 0.41, R 2 ¼ 0.17) and minimalrelationship for four syllables (r ¼ 0.01, R 2 ¼ 0.00).

Figure 2 illustrates the interaction between Englishnonword length and age at first English exposure.OLS regression estimates showed that for two-syllable(r ¼ 20.15, R 2 ¼ 0.02) and three-syllable(r ¼ 20.18, R 2 ¼ 0.03) nonwords, there is a negativerelationship between age at first English exposure andpercentage of nonwords correct. For four-syllablelength nonwords, later first exposure is related tohigher percentage of nonwords correct (r ¼ 0.26,R 2 ¼ 0.07).

Spanish

Figure 3 shows the interaction between nonword lengthand age at first English exposure for Spanish NWR. Fortwo syllable nonwords, there is a negative relationshipbetween age at first English exposure and percentage ofnonwords correct (r ¼ 20.16, R 2 ¼ 0.03). Laterexposure to English is related to higher percentage ofnonwords correct for three-syllable (r ¼ 0.08,R 2 ¼ 0.01) and four-syllable length nonwords(r ¼ 0.40, R 2 ¼ 0.16).

Discussion

The process of repeating nonwords involves listeningto sounds in a sequence, remembering them, andrepeating them back. NWR is routinely considered tobe a measure of phonological short-term memorybecause phonological storage, phonological represen-tation, and speech production play large roles in theprocess, especially when the syllable sequences are lowin word-likeness and the phoneme sequences are low infrequency. In this study, we do not attempt todetermine which of these systems plays a bigger role inrepeating nonwords. Rather, we examine the perform-ance of children who have knowledge of two languagesystems and varying experiences with those languages toexplore the effects of language knowledge and

Table

5.

Model2:Testofinteractions

En

glis

hSp

anis

h

Inte

ract

ion

sN

um

ber

ofd

.f.

Den

d.f

.F

-val

ue

Pr.

FN

um

ber

ofd

.f.

Den

d.f

.F

-val

ue

Pr.

F

Sem

anti

cs*N

onw

ord

len

gth

(Mod

el2

a)2

48

0.4

70

.62

67

24

30

.20

0.8

21

4M

orp

hos

ynta

x *N

onw

ord

len

gth

(Mod

el2

a)2

48

3.1

50

.05

16

24

30

.45

0.6

37

6In

pu

tb

yn

onw

ord

len

gth

(Mod

el2

b)

24

81

.96

0.1

52

42

43

0.1

90

.82

97

Ou

tpu

tb

yn

onw

ord

len

gth

(Mod

el2

b)

24

80

.90

0.4

14

12

43

0.8

00

.45

62

Age

by

non

wor

dle

ngt

h(M

odel

2c)

24

80

.17

0.8

40

42

43

1.5

10

.23

33

Age

atfi

rst

En

glis

hex

pos

ure

by

non

wor

dle

ngt

h(M

odel

2c)

24

86

.12

0.0

04

32

43

7.3

20

.00

18

Age

*In

pu

t(M

odel

2d

)1

43

0.0

10

.90

79

13

80

.49

0.4

86

5A

ge*O

utp

ut

(Mod

el2

d)

14

30

.06

0.8

05

21

38

1.5

50

.22

05

Not

e:N

um

ber

ofd

.f.¼

nu

mber

ofgr

oup

s-

1;

Den

d.f

.¼

n-

nu

mber

ofgr

oup

s.


experience on children’s abilities to represent, store, andproduce nonwords. To explore these relationships, weexamined how bilingual children performed on twoNWR tasks (one English-like and one Spanish-like)with low word-likeness and low phoneme sequencefrequencies. Our goals were to assess NWR perform-ance across Spanish and English language learners,and to explore the relationships between NWRperformance and performance on measures of seman-tics and morphosyntax in English and Spanish.

The results from this study reveal two major

patterns. First, NWR performance was similar across

English and Spanish with differences in performance

patterns based on accuracy. NWR performance in both

English and Spanish was also significantly correlated to

cumulative language experience. Second, there were

significant correlations between NWR and morpho-

syntax in both English and Spanish, and no correlations

with semantics.

Figure 1. English nonword repetition (NWR) score as outcome.

Figure 2. English nonword repetition (NWR) score as outcome.


With respect to overall patterns of NWRperformance similarities, children’s accuracy at repeat-ing nonwords in both English and Spanish decreasedwith word length which is consistent with previousstudies (Dollaghan and Campbell 1998, Girbau andSchwartz 2007, Sahlen et al. 1999, Ebert et al. 2008).NWR performance in Spanish was higher than inEnglish overall. Yet, the higher accuracy in SpanishNWR appears to come from differences between thelanguages and not within the subjects.

Spanish is characterized by frequent multi-syllabicwords comprised mainly of CV combinations.Children who have experience with many multi-syllabic words in their language(s) have that knowledgein their long-term language memory. Spanish languageexperience may have helped the children with moreexperience use their phonological working memorysystems more effectively to repeat Spanish nonwords.However, the descriptive pattern of more accurateperformance for the Spanish-like items than theEnglish-like items was consistent across all children.Clearly, this pattern of findings is not consistent with anexplanation that focuses solely on the role of priorknowledge of Spanish or the nature of Spanish. Recallthat the phonological system of Spanish is masteredrelatively early compared to English. This earliermastery may be due to the smaller number of phonemesand contrasts in the sound inventory of Spanish. Fewerphonemes in the system permits longer CV stringsbecause there are relatively fewer options in eachposition of the CV syllable. Fewer options coulddecrease memory load in comparison to that of English

allowing children to produce longer strings of syllables.Bilingual English/Spanish children have the same levelof complexity in their phonetic inventories, as domonolingual children. Yet, their phonetic systemsare separate, as demonstrated by variations intheir phonetic inventories (Fabiano-Smith andBarlow 2009).

Future research with Spanish NWR needs toinclude five syllable nonwords for the trajectory ofaccuracy across syllable lengths to look similar toEnglish. Other studies have included longer nonwordsin multi-syllabic languages including Portuguese(Santos et al. 2006), Swedish (Sahlen et al. 1999),and Spanish (Girbau and Schwartz 2007).

The significant interaction between word lengthsand age of first exposure to English was consistent forboth English and Spanish. The later a child was firstexposed to English, the more accurate they were atrepeating four-syllable nonwords. In English, laterexposure to English resulted in slightly lowerperformance on two- and three-syllable nonwords.In Spanish, later exposure to English was not related toperformance on two- and three-syllable nonwords.These interactions may reveal an effect of long-termexperience and practice with a language that results inmore ingrained, automatic production. Those childrenwho have more cumulative experience with Spanish(as noted by later exposure to English) repeat longernonwords more accurately. Although these interactionsrequire replications in larger samples, the findingsreflect the multi-syllabic nature of the Spanishlanguage. Spanish is a highly inflected language

Figure 3. Spanish nonword repetition (NWR) score as outcome.


in which linguistic complexity is gained by producinglonger words. More practice with this inflected systemleads to better performance on NWR. Children withmore cumulative experience with multi-syllabic words,are more efficient at repeating longer nonwordsregardless of the language they reflect.

Children who had more output in Spanish wereslightly less accurate at repeating Spanish nonwords.This finding has limited practical significance given thata 1% increase in Spanish output was related to a 0.3%decrease in PPC. The measure of Spanish outputreflects a child’s current language use. Children oftenhave shifts in their current output depending oncontext, knowledge, and preference. In contrast, the ageof first exposure to English reflects a child’s cumulativelanguage experience. In this case, cumulative languageexperience was more important in determining NWRperformance than current language experience. Thisexperience with manipulating more syllables in Spanishinfluences the ability to manipulate more syllables innonwords.

Another explanation of the possible influence onperformance is that the nonwords in one language mayappear word-like in the other languages. Here forexample, nonword-like stimuli were used in bothlanguages. The English nonwords such as veitachaidoiphave many open syllables, are comparable in length toSpanish words, and the consonants are all permissible inSpanish. Spanish words conform to Spanish phonotac-tic rules but they include low frequency closed syllablesthat are less frequent in Spanish (e.g., merfas).The vowels are specific to the target language in eachcase. While this drift may be inevitable, it is importantto monitor whether or not the nonwords of onelanguage contain morphemes of the other that mightinadvertently recruit linguistic knowledge of the otherlanguage. Recall that adults judged the nonwords in thisstudy to be like the target language.

The second finding that emerged in this study wasthe relationship between morphosyntax and NWR inboth English and Spanish. Our analysis demonstratesthat NWR was positively related to the morphosyntaxscores. Effect sizes revealed these relationships to bestrong. Morphosyntax scores accounted for 22% ofthe variance in PPC for English and 26% for Spanish.This relationship is consistent with previous work(Adams and Gathercole 1995, Sahlen et al. 1999).Children tapped into similar skills to complete NWRand morphosyntax tasks. It appears that the betterchildren are at manipulating morphemes, the betterthey are at repeating nonwords.

The interaction trend between morphosyntax andsyllable length in English showed that better perform-ance on English morphosyntax yielded better perform-ance on two- and three-syllable nonwords. Yet, the

same pattern was not seen for four-syllable nonwords.There was no relationship between morphosyntax andnonword performance for four-syllable nonwords inEnglish. This suggests that children were tapping intothe same mechanisms to repeat two- and three-syllablenonwords as they did to mediate morphosyntax tasks.However, four-syllable English nonword results did notdemonstrate the same relationship. Possible sources ofdifference could be greater practice producing multi-syllabic words or lessoned articulatory or memorydemands with Spanish four-syllable words due to theconsonant vowels patters that predominate in Spanish.Recall that overall children had more exposure andpractice with Spanish. Their scores on both thesemantics and morphosyntax screeners were higher inSpanish.

These results provide further evidence that childrenmay be demonstrating a practice effect. The more theyare able to manipulate morphemes, the more accuratethey are at repeating nonwords. The interactionbetween first exposure to English and syllable lengthprovides converging evidence that the more practice achild has manipulating syllables, the better they are ableto repeat four-syllable nonwords in both Spanish andEnglish.

Overall, differences in NWR performance were notdependent on the test. Rather, children’s knowledgeand experience with language(s) affected performance.The children demonstrated higher scores in Spanishsemantics than in English semantics. Exposure andexperience with English is increasing for all childrenbut, as a group, they had more experience in Spanishthan in English. Thus, these children are in a state oftransition as they become more familiar and productivewith the English language.

Conclusion

This study of NWR with both languages of bilingualchildren adds important information concerning theinteraction of phonological working memory andlanguage experience. Children’s knowledge and famili-arity with language(s) interact with the structure of thelanguage(s). Phonological short-term memory skills asmeasured by NWR performance rely on the child’sadeptness as a learner and on their language experience.Children’s language experiences may affect theirabilities to mediate morphosyntactic tasks duringassessment and in academic settings as shown by strongeffect sizes. Different relationships are observed withNWR depending on language experiences. This hasimplications for language teaching as bilingual childrenconstantly shift their language dominance between theirtwo languages. Their performance on tasks that usephonological short-term memory skills may vary as their


dominance shifts. These results should be interpretedcautiously due to the overall small sample size. Furtherresearch with bilingual children will help interpret therelationship between language experience and phono-logical working memory.

Acknowledgements

Declaration of interest: The authors report no conflicts of interest.The authors alone are responsible for the content and writing of thepaper.

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