INT J LANG COMMUN DISORD, SEPTEMBER–OCTOBER 2011, VOL. 46, NO. 5, 564–578 Research Report A cross-linguistic study of real-word and non-word repetition as predictors of grammatical competence in children with typical language development Marco Dispaldro†, Patricia Deevy‡, Gianmarco Alto´ e†, Beatrice Benelli† and Laurence B. Leonard‡ †Universit` a di Padova, Padua, Italy ‡Purdue University, West Lafayette, IN, USA ((Received 17 December 2009; accepted 5 October 2010)) Abstract Background: Although relationships among non-word repetition, real-word repetition and grammatical ability have been documented, it is important to study whether the specific nature of these relationships is tied to the characteristics of a given language. Aims: The aim of this study is to explore the potential cross-linguistic differences (Italian and English) in the relationship among non-word repetition, real-word repetition, and grammatical ability in three-and four-year-old children with typical language development. Methods & Procedures: To reach this goal, two repetition tasks (one real-word list and one non-word list for each language) were used. In Italian the grammatical categories were the third person plural inflection and the direct- object clitic pronouns, while in English they were the third person singular present tense inflection and the past tense in regular and irregular forms. Outcomes & Results: A cross-linguistic comparison showed that in both Italian and English, non-word repetition was a significant predictor of grammatical ability. However, performance on real-word repetition explained children’s grammatical ability in Italian but not in English. Conclusions & Implications: Abilities underlying non-word repetition performance (e.g., the processing and/or storage of phonological material) play an important role in the development of children’s grammatical abilities in both languages. Lexical ability (indexed by real-word repetition) showed a close relationship to grammatical ability in Italian but not in English. Implications of the findings are discussed in terms of cross-linguistic differences, genetic research, clinical intervention and methodological issues. Keywords: non-word repetition, real-word repetition, grammatical ability, crosslinguistic difference, typical language What this paper adds What is already known on this subject Children’s scores on non-word repetition tasks are good predictors of measures of grammatical development. Moreover, the non-word-repetition task is a clinical marker that can identify children with language difficulties. Since non-word repetition does not rely on lexical representations, phonological short-term memory contributes strongly to this task. In contrast, in the repetition of real words the phonological input activates the phonological form of the lexical representation stored in long-term memory. For this reason real words are easier to repeat than non-words. What this study adds The abilities underlying non-word and real-word repetition could contribute in different ways to the development of grammatical ability, depending on the features of the language learned by the child. Address correspondence to: Marco Dispaldro, Department of Development Psychology and Socialization, Universit` a di Padova, Via Venezia, 8, Padua I-35131, Italy; e-mail: [email protected]International Journal of Language & Communication Disorders ISSN 1368-2822 print/ISSN 1460-6984 online c 2011 Royal College of Speech & Language Therapists DOI: 10.1111/j.1460-6984.2011.00008.x
Transcript
INT J LANG COMMUN DISORD, SEPTEMBER–OCTOBER 2011,VOL. 46, NO. 5, 564–578
Research Report
A cross-linguistic study of real-word and non-word repetition as predictorsof grammatical competence in children with typical language development
Marco Dispaldro†, Patricia Deevy‡, Gianmarco Altoe†, Beatrice Benelli† and Laurence B. Leonard‡†Universita di Padova, Padua, Italy‡Purdue University, West Lafayette, IN, USA
((Received 17 December 2009; accepted 5 October 2010))
Abstract
Background: Although relationships among non-word repetition, real-word repetition and grammatical abilityhave been documented, it is important to study whether the specific nature of these relationships is tied to thecharacteristics of a given language.Aims: The aim of this study is to explore the potential cross-linguistic differences (Italian and English) in therelationship among non-word repetition, real-word repetition, and grammatical ability in three-and four-year-oldchildren with typical language development.Methods & Procedures: To reach this goal, two repetition tasks (one real-word list and one non-word list for eachlanguage) were used. In Italian the grammatical categories were the third person plural inflection and the direct-object clitic pronouns, while in English they were the third person singular present tense inflection and the pasttense in regular and irregular forms.Outcomes & Results: A cross-linguistic comparison showed that in both Italian and English, non-word repetition wasa significant predictor of grammatical ability. However, performance on real-word repetition explained children’sgrammatical ability in Italian but not in English.Conclusions & Implications: Abilities underlying non-word repetition performance (e.g., the processing and/orstorage of phonological material) play an important role in the development of children’s grammatical abilities inboth languages. Lexical ability (indexed by real-word repetition) showed a close relationship to grammatical abilityin Italian but not in English. Implications of the findings are discussed in terms of cross-linguistic differences,genetic research, clinical intervention and methodological issues.
What this paper addsWhat is already known on this subjectChildren’s scores on non-word repetition tasks are good predictors of measures of grammatical development.Moreover, the non-word-repetition task is a clinical marker that can identify children with language difficulties.Since non-word repetition does not rely on lexical representations, phonological short-term memory contributesstrongly to this task. In contrast, in the repetition of real words the phonological input activates the phonologicalform of the lexical representation stored in long-term memory. For this reason real words are easier to repeat thannon-words.
What this study addsThe abilities underlying non-word and real-word repetition could contribute in different ways to the developmentof grammatical ability, depending on the features of the language learned by the child.
Address correspondence to: Marco Dispaldro, Department of Development Psychology and Socialization, Universita di Padova, Via Venezia,8, Padua I-35131, Italy; e-mail: [email protected]
In this paper, we explore potential cross-linguisticdifferences (between Italian and English) in therelationship among non-word repetition, real-wordrepetition, and grammatical ability in three-and four-year-old children with typical language development.Although relationships among these abilities have beendocumented (Botting and Conti-Ramsden 2001, Chiatand Roy 2007, Dispaldro et al . 2009), their precisenature remains elusive. By studying how these relation-ships change as a function of the language being acquiredby the child, we may be able to come to a betterunderstanding of the interacting learning mechanismsthat may be involved.
Non-word and real-word repetition
Studies have shown that vocabulary size plays animportant role in the development of children’sgrammatical abilities both in typical and atypicallanguage development (Bates and Goodman 1999,Caselli et al. 1999, Devescovi et al . 2005). For example,the early appearance of grammatical morphemes isrelated to the number of words (especially verbs) ina child’s vocabulary.
To the extent that the ability to succeed on real-word repetition tasks could reflect lexical ability, arelationship between real-word repetition performanceand grammatical ability can be expected. For Italian,this appears to be the case: Dispaldro et al . (2009)found that a children’s ability to repeat a list of realwords was strongly related to their ability to produceverb inflections and clitic pronouns.
Dispaldro et al . (2009) also examined non-wordrepetition ability in the same Italian-speaking preschoolchildren. Previous studies of English had found non-word repetition to be related to grammatical ability(Botting and Conti-Ramsden 2001, Chiat and Roy2007). Similarly, Dispaldro et al . (2009) found thatnon-word repetition served as a significant predictor forgrammatical ability in Italian when considered alone;however, these investigators also found that real-wordrepetition had greater predictive value than non-wordrepetition.
The authors interpreted this closer relationshipbetween real-word repetition and Italian grammaticalability as a consequence of the fact that repetition of realwords involves activation of the phonological form of alexical representation in long-term memory (Chiat andRoy 2007). This lexical representation captures not justphonological knowledge, but also semantic knowledge.In contrast, non-word repetition has links to lexicalrepresentations only in indirect ways; for example, non-words can differ in how word-like they are in the child’s
language (Dollaghan et al . 1993, Gathercole 1995), andhow well they approximate the phonotactic sequencesof words in the language (Edwards et al . 2004, Munsonet al . 2005). Such factors influence children’s non-wordrepetition accuracy. However, when lexical influencesare controlled for, it is phonological short-term memorythat is primarily responsible for non-word repetitionperformance (Gathercole et al . 1994). It should benoted that, in addition to phonological memory, otherskills and knowledge such as speech perception andmotor planning also contribute to performance onthis complex task (Coady and Evans, 2008; Gathercole2006).
The results described here for Italian-speakingchildren raise interesting questions about the relation-ship between the features of the language spoken by achild and differences between real-word and non-wordrepetition in their value as predictors of grammaticalability. At present no studies known to the authors haveinvestigated this question.
Crosslinguistic differences between Italianand English
We believe that it is important to discover whetherthere are differences between non-word repetition andreal-word repetition cross-linguistically and whetherthese differences are tied to the characteristics of agiven language. In fact, differences in the grammati-cal characteristics of languages might well influence therelative accuracy of non-word repetition and real-wordrepetition as predictors of children’s grammatical ability.
In this study, we compare English-and Italian-speaking children, and hypothesize that the relativestrength of non-word repetition and real-word repetitionas predictors of grammatical ability will differ acrossthese two languages.
English is a language with a sparse grammati-cal morphology, relative to Italian (Radford, 2004).Although nouns and verbs can be inflected, these lexicalforms appear much more frequently in the language asbare stems than as inflected forms. Infinitives are barestems (e.g., kick in “We saw her kick the ball”; “He mightkick the ball”; “They want to kick the ball”) as are finite“zero-marked” forms (e.g., I kick, you kick, we kick,they kick). Most inflections are consonantal in nature(e.g., kicks, kicked ), thus differing only minimally fromthe bare stem equivalents of the same words. Withsuch limited variations in the phonological forms oflexical items, and dependence on small phonologicaldifferences between bare stem forms and inflected forms,English-speaking children’s acquisition of grammaticalmorphology may be more tied to the ability to focus on,and retain, small phonological differences than wouldbe true for children learning other types of languages. As
a consequence it is possible that these characteristics ofgrammar result in a stronger relationship between non-word repetition and grammatical ability in preschoolEnglish-speaking children.
We might expect a stronger tie between the lexiconand grammar for English irregular verbs since theseforms may be acquired and represented as completewords (e.g, He wrote,I ate) whereas regular verbs arerepresented as bare stems with rule-based addition of thepast tense morpheme (Marcus et al. 1992). However,it is well known that especially in the first phase oflanguage acquisition children often treat irregular verbsas regular verbs (e.g., He writed , I eated ) (overregulari-sation) (Marcus et al. 1992).
In contrast, Italian is a language in which nouns,verbs, adjectives, and pronouns are always inflected(Scalise 1994; Trifone and Palermo 2000). Nounsand adjectives will always be marked for number andgender (e.g. “little” piccolo, piccola, piccoli, piccole);finite verbs will always be marked for person, number,and tense (e.g., “I eat” mangio, “we eat” mangiamo,“they ate” mangiavano), and nonfinite verbs will alwayscarry an infinitive or participle inflection (e.g., “[to]eat” mangiare, “eating” mangiando, “eaten” mangiato);pronouns, for example clitic pronouns, will always bemarked for person, number and gender (e.g., “theyeat them” le mangiano [feminine] or li mangiano[masculine], “they eat it” la mangiano [feminine] orlo mangiano [masculine]). Because in Italian the wordscarry grammatical marking as well as meaning, the tiesbetween real-word repetition and grammatical abilitymight be expected to be relatively strong.
In addition, the many alternative phonologicalforms of each noun, pronoun, verb, and adjective(e.g., “pretty” bello, bella, belli, belle) that result fromthe inflectional nature of Italian, require attention tothis phonological variation on the part of childrenlearning this language. Thus, non-word repetitionability will have predictive value also in Italian. However,the phonological differences among different inflectedforms of the same word in Italian depend on detectingdifferences in vowels (e.g., “pretty” /ˈbe l:o/ vs. /be l:a/)or whole syllables (e.g., “they run” /ˈko r:o no/ vs.“we run”/ˈko r:ja mo/). This means that in Italian thephonological contrasts are more salient and thereforesensitivity to small phonological differences, in order todiscover the grammatical rules, could be less crucial thanis the case for English.
Objectives and predictions
The aim of the present work is to investigate whetherthere are cross-linguistic differences between real-wordand non-word repetition in their predictive strengthas regards grammatical ability. The characteristics of
English and Italian led us to expect that non-wordrepetition would account for a greater percentage ofvariance in children’s scores on measures of grammar inEnglish, whereas real-word repetition would account fora greater percentage of variance in children’s scores ongrammatical measures in Italian.
In order to investigate these objectives, tworepetition tasks (one real-word list and one non-wordlist for each language) were presented to three-andfour-year-old children with typical language develop-ment. The grammatical categories were the following:in Italian, the third person plural inflection (e.g., “theydrink” bevono) and the direct-object clitic pronouns(e.g., “they eat it” lo mangiano) and in English, the thirdperson singular present tense (e.g., she teaches) inflectionand the regular and irregular past tense (e.g., he painted,she ate). These particular grammatical morphemes werechosen because they have been identified as clinicalmarkers of specific language impairment (SLI) in theirrespective languages. Thus, mastery of these morphemesserves as a good measure of typical and atypical languagedevelopment (Bortolini et al . 2006, Conti-Ramsdenet al. 2001, Rice and Wexler 1996).
The portion of the study on Italian is a replicationof Dispaldro et al. (2009). This new sample of Italianchildren could enable us to confirm and extend theprevious findings on the effect of lexical representationon grammatical ability in Italian.
Method
Participants
A total of 78 children with typical language develop-ment participated in this study: 48 of them weremonolingual Italian speakers while 30 were monolin-gual English speakers. Each language group was furthersubdivided into three age groups with a mean age of 3;0(years; months), 3;6, and 4;0 (see Table 1). All researchprocedures were conducted according to guidelines forthe protection of human participants of the authors’institutions; parental consent was obtained for eachchild before inclusion in the study.
Italian-speaking population
The Italian-speaking children were recruited fromnursery schools in Padua (Italy). Children were not
included if they showed any language, articulatory,hearing, neurological or psychiatric deficit according toparent and teacher report.
English-speaking population
The English-speaking children were recruited throughthe Department of Speech, Language, and HearingSciences at Purdue University (West Lafayette, Indiana,USA). The Verbal Comprehension subtest of the ReynellDevelopmental Language Scales (Reynell and Gruber1990) was used as a general measure of receptivelanguage development. An articulation screener (Riceand Wexler 2001) was used to ensure that allchildren could produce the consonants required by theexperimental grammatical task (i.e., /s/, /z/ and /t/, /d/ inthe word-final position for the morphemes third singularpresent tense –s and past tense –ed). All children passeda pure-tone hearing screening bilaterally (20 dB HL) at500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz (AmericanSpeech-Language-Hearing Association 1997).
Procedure and Materials
The Italian-speaking children were tested individuallyin a quiet room in their nursery school in Padua.The English-speaking children were assessed individ-ually in a quiet room in the Speech and Hearing Clinicat Purdue University. For all children, the tasks wereadministered over two or three sessions (one session perday), each lasting 20 minutes. All children’s responseswere recorded on a computer using a Sony ECM CZ-10 microphone and Audacity software. Responses weretranscribed after the experimental session by a nativespeaker of the language tested (the first author for Italianand the second author for English).
Repetition Tasks
The repetition stimuli were administered live-voice. Each list included three practice items. Theexperimenter said each word aloud, encouraging thechild to repeat each one as accurately as possible. Practiceitems were repeated as necessary until the child wascomfortable and responsive. The experimental stimuliwere then presented, with each target word spokenonly once. Non-contingent positive verbal reinforce-ment (e.g., “You’re doing so well!”) was given through-out the task and no corrective feedback was given.Transcription of responses was done after the experimen-tal session. The order of stimuli presentation within eachlist was fixed. The lists themselves were administered ondifferent days, in counterbalanced order, with half ofthe children receiving the real-word list first and halfreceiving the non-word list first.
Italian repetition task
The task was composed of a list of 16 real wordsand a list of 16 non-words, for a total of 32 targets(see Appendix A for a complete list) (Dispaldro et al .2009). The words contained in the real-word list areassumed to be known by preschool children, basedboth on norms reported in the Barca et al . (2002)database and the results showed in Dispaldro et al.(2009). They were selected on the basis of their familiar-ity to reduce possible effects of differences in experiencerelated to social-cultural background. The non-wordstimuli closely matched the real words: for each realword, a non-word was constructed that used the sameinitial phoneme and replaced the other phonemes withones similar in sonority or manner of articulation (forexample, the non-word /’bofo/ was created to match thereal word /’bava/).
The real-word and non-word lists containedequal numbers of two-and three-syllable words.Moreover, real-and non-word targets were matchedfor syllabic structure. Half the stimuli had asimple (Consonant/Vowel (CV)) syllabic structure; forexample, the real-word “sugo” and non-word “simi”had [CV CV] structure); and half the stimuli had acomplex syllabic structure (CCV or CVC); for example,the real-word “spada” and the non-word “frive” had[CCV CV] structure). All words had the same prosodicstructure, with stress on the word’s penultimate syllable.To minimize the articulatory difficulty of the repetitiontasks, the stimuli were constructed such that the words’initial consonants were those known to be in theinventory of three-year-old children. To control forthe influence of phonological representations storedin long-term memory (Edwards et al . 2004, Munsonet al . 2005), both real and non-words were matched onneighborhood density and on phonotactic probability.
English repetition task
For the English real-word and non-word stimuli, weused the Preschool Repetition Test (PSRep) (Chiatand Roy 2007) (see Appendix B for a complete list),adapting it in two ways. First, because the Italianrepetition task did not include one-syllable words, wedid not use the PSRep’s one-syllable real or non-words.Second, the PSRep uses Southern British StandardEnglish pronunciation (for example, pronouncing thereal word ‘person’ as /ˈpɜ s@n/ and the correspond-ing non-word ‘serpen’ as /ˈsɜ p@n/). Standard AmericanEnglish pronunciation was targeted in this study, thusadult pronunciations would be /ˈpɝ sn/ and /ˈsɝ p@n/for these words.
After these modifications, the PSRep test includedtwo lists of 12 stimuli each: one list of real words and one
568 M. Dispaldro et al.
list of non-words. The non-word targets (for example/lɅ ˈpis/) were created by reversing the consonants ofthe respective real word (for example /pɅ ˈlis/, “police”)while maintaining vowels in their original positions.Real-word and non-word lists had equal numbers of twoand three syllable words. Given the prosodic structureof English words the stimuli had the follows features:for two-syllable words the prosodic structure was SW(Strong/stressed – Weak/unstressed) or WS, while forthree-syllable words the structure are SWS or WSW(For further details about the stimuli, see Roy and Chiat2004).
Grammatical Tasks
Italian grammatical tasks
The morphological categories used were the third-personplural inflection in the indicative present tense (bevono[they drink]) and the third-person direct object cliticpronoun (la spinge [she/he pushes it]. The indicativepresent tense in Italian marks person (first, second,and third) and number (singular and plural). BecauseItalian is a pro-drop language and verb morphologyallows identification of the subject, the subject nounis not obligated in the child’s responses (for example,the response ‘mangiano’ instead ‘loro mangiano’ [theyeat] is acceptable). The direct object clitic pronounin Italian marks person (first, second, and third),number (singular and plural), and grammatical gender(masculine and feminine). The third-person directobject clitic pronouns assume two singular forms(masculine ‘lo’ and feminine ‘la’) and two plural forms(masculine ‘li’ and feminine ‘le’).
These morphemes constitute clinical markers inItalian; that is, Italian preschool children are accurate inthe use of these grammatical categories (Leonard et al .2002), while children with SLI show problems withthem (Bortolini et al . 2006). Studies have shown thatItalian-speaking children with SLI can be readily singledout from their typically developing peers on the basis oftheir inconsistent use of such morphemes. Measures ofthis type exhibit both high sensitivity and specificity(Bortolini et al . 2006). That is, they succeed in identify-ing children with SLI (sensitivity) while also correctly“passing” those children who have typical language(specificity).
In order to elicit the third-person plural presenttense inflection, 18 colored drawings, each depictingan action, were presented on a computer screen (seeAppendix C for a complete list) (Bortolini et al . 2006,Dispaldro et al . 2009, Leonard et al . 2002). Theexaminer prompted the child to describe each picture byasking ‘Cosa succede qui?’ (‘What’s happening here?’).This question was used in order to elicit production ofthe target morpheme (e.g.,‘dormono’ [they sleep]).
Nine items elicited the third-person plural inflection(through an action performed by two individuals; forexample, two sleeping children) and nine were used toelicit the third-person singular inflection (through anaction performed by one child; for example, one sleepingchild). The third-person singular items were included inorder to avoid an effect of perseveration on the pluralform. These were excluded from the analyses. Singularand plural drawings were presented in random order.Three practice items were used to familiarize the childrenwith the task.
In order to elicit the third-person direct object cliticpronoun, 16 pairs of colored drawings depicting twoconsequential actions were presented (Bortolini et al .2006, Dispaldro et al . 2009, Leonard et al . 2002).The examiner described the first of the two drawingsand prompted the child to complete the sentenceby describing the second. For example, [first picture]Experimenter: ‘La bambina compra il gelato e poi..’;[second picture] Child: ‘lo mangia’ (Experimenter: Thegirl buys an ice cream and then.. Child: she eats it’)(see Appendix D for a complete list). The first drawingappeared on the left-hand side of the computer screen,while the second was on the right-hand side. The orderof presentation of items was random. To familiarizethe children with the task, three practice items wereused.
English grammatical tasks
The morphemes used for English were the third-personsingular inflection in the indicative present tense (he/shehelps) and the past tense in regular and irregular forms(he/she painted ; he/she caught). These morphemes areconsidered clinical markers of SLI in English, capable ofdistinguishing between children with typical languageand children with SLI (Conti-Ramsden et al. 2001,Rice and Wexler 1996). The Test of Early Grammat-ical Impairment (TEGI, Rice and Wexler 2001) wasused to elicit these morphemes.
The third-person singular portion of the TEGI wasdesigned to assess correct grammatical usage of the third-person singular -s. The test consisted of 10 coloreddrawings depicting an action. The experimenter askeda question about the drawing to which the child wasobligated to respond using a third-singular verb form(for example, Experimenter: ‘Here is a teacher. Tell mewhat the teacher does’; Child: ‘A teacher teaches.’)
To assess the child’s ability to produce the past tensein regular verbs (-ed ) and irregular verbs, we used the pasttense portion of the TEGI. This consisted of 18 pairsof colored drawings depicting two sequential actions.The first picture showed a person performing an action;the second picture showed the same person after he orshe had finished the action. The experimenter read a
sentence related to the first picture and then promptedthe child to describe the second picture using the pasttense form. For example, [first picture] Experimenter:“Here the boy is raking. Now he is done. Tell me whathe did.”; [pointing to second picture] Child: “He raked.”The task was composed of 10 regular and 8 irregular verbitems.
Scoring
Italian and English Repetition Tasks
Children’s repetitions were transcribed using theInternational Phonetic Alphabet (IPA) (broad transcrip-tion) by native speakers of each language (the first andsecond author for Italian and English, respectively) whowere trained in phonetic transcription.
For both languages and for both word types,productions were scored using the method of Dollaghanand Campbell (1998). Each phoneme produced by thechild was compared to its target and scored as incorrectif the child omitted it or substituted another phoneme.Phoneme additions and distortions were not counted aserrors. If one or more syllables were omitted, the syllablesequence produced by the child was aligned to thetarget using the vowels as syllable anchors; once aligned,scoring of each phoneme proceeded as described. Non-responses were not included in the analyses.
The total number of phonemes repeated correctlywas then divided by the total number of target phonemesto obtain a percentage of phonemes correct (PPC)score at each real-word and non-word length (2 and3 syllables).
Grammatical Tasks
Italian grammatical tasks
For third-person plural inflection in the indicativepresent tense, productions of the inflection accuratelymarking person (third), number (plural) and tense(indicative) were scored as correct (for example,‘mangiano’ [they eat] for a drawing with two childreneating). Certain overregularizations were also scoredas correct. In Italian some verbs are irregular in theirroot; an over-regularization is a production in whichthe verb’s regular root is used instead of its irregularroot. For example, for the infinitive verb /sal-ire/ [togo up], the child could produce the overregularization“sal-ono” instead of the correct irregular form,“salg-ono”.These cases were scored as correct because the correctthird-person plural inflection was used. All forms thatdid not correctly mark the target for person, number,or tense were considered errors (for example, the child
produced ‘mangia’ [s/he eat] for a drawing with twochildren eating).
Responses in the direct object clitic pronoun taskwere scored as correct if the pronoun agreed in genderand number with the direct object, for example,Experimenter: “I bambini raccolgono le mele e poi..Child: le mangiano” [Experimenter: The boys pick theapples and then.. Child: they eat them]. Responses thatwere scored as errors included the omission of thepronoun (for example, “mangiano” [they eat]); an errorof agreement in gender or number with the direct object(for example, “la mangiano” instead of “le mangiano”[they eat it]); and use of the direct object noun phraseinstead of the clitic (“mangiano le mele” [they eatthe apples]). For both morphemes tested, incompleteresponses or ambiguous responses and non-responseswere excluded from the analyses.
English grammatical tasks
For the third-person singular probe, productions werescored as correct if they included a third-person singularsubject followed by a third-person singular present tenseverb form (for example, “S/he paints” ). Productionswere scored as incorrect if the morpheme was omittedin a third-person singular context (for example, “S/hepaint”) or the verb was double marked (for example,“S/he paintses” ). Scores were calculated by dividing thetotal number of correctly marked verbs by the totalnumber attempted (correct and incorrect responses)and multiplying by 100 to get a percentage correctscore. Responses were considered unscorable if thechild produced any verb form or tense other than thethird-person singular present tense (for example, “S/heplayed”).
For the past tense probe, regular verbs were scoredseparately from irregular verbs. For regular verbs, aresponse was considered correct if it included a subjectfollowed by a correct production of the regular pasttense form of the verb (for example, “S/he painted” ). Aresponse was considered incorrect if the child omittedthe morpheme –ed in a past tense context (for example,“S/he paint”). For irregular verbs, a response wasconsidered correct if it included a correctly formulatedirregular past tense (for example, “S/he wrote” ) or if theverb was overregularized (for example, “S/he wroted”or “S/he writed”). A response was considered incorrectif it was not correctly formulated (for example, “S/hewrite”). The percentages correct of the total past tenseare an average of the percentages correct for regular andirregular forms. Responses were considered unscorableif the child’s production included any verb tense otherthan past (for example. “He will paint”).
570 M. Dispaldro et al.
For both morphemes, unscorable responses andnon-responses were excluded from the analyses.
Results
Italian Language
Repetition Tasks
The mean PPCs and standard deviations for each agegroup are reported in Table 2. Means are reported for allwords (TPPC, total percentage of phonemes correct),for two syllable words (2PPC), and for three syllablewords (3PPC).
A mixed-design analysis of variance (ANOVA) wascarried out on the percentage of phonemes correct (PPC)as a dependent variable, with Word Type (real-word listand non-word list) and Word Length (two and threesyllables) as within-subjects variables and Age level (3;0,3;6, and 4;0 years) as a between-subjects variable.
The analysis showed a significant main effect of Age(F(1, 45) = 3.870, p = .028, ηp2 = .147); post-hoc(Bonferroni) showed that 4;0 year-olds scored higher(95%) than 3;0 yearolds (90%). A significant maineffect of Word Type (F(1, 45) = 22.828, p < .0001,ηp2 = .337) was found which showed that childrenrepeated real words (94%) more accurately than non-words (91%). There was also a significant main effect ofWord Length (F(1, 45) = 6.211, p = .016, ηp2 = .121)such that two-syllable words were easier (93%) to repeatthan three syllable-words (91%). Finally, there was asignificant two-way interaction between Word Type andSyllable Length (F(1, 45) = 4.255, p = .045, ηp2 =.086) which showed that as length in syllables increased,accuracy of repetition decreased to a greater degreefor non-words than for real words. Finally, we testedfor a correlation between performance on real-wordrepetition and non-word repetition and found that the
Table 2. Mean percentage phonemes correct (and standarddeviations) at each word length for real words and non words
two were highly correlated (r = 0.807, p < 0.0001). Thissuggests that although differences in lexical knowledgeled to differences in performance, real-word and non-word repetition tasks also tap many of the same underly-ing abilities (e.g., phonological working memory, speechperception, and motor planning).
Grammatical tasks
The mean percentages correct for clitic pronounsand the third-person plural inflection are shown inTable 3 (both variables were normally distributed: inKolmogorov-Smirnov test, all ps > 0.05). A mixed-design ANOVA was carried out on the percentagesof correct productions with Grammatical Categories(pronouns and verb inflections) as a within-subjectsvariable, and Age (3;0, 3;6, and 4;0 years old) as abetween-subjects variable.
The analysis showed a significant main effect of Age(F(2, 45) = 4.755, p = 0.013, ηp2 = 0.174); Bonferronipost-hoc testing at the 0.01 level revealed that 4;0 year-old children scored better (77%) than 3;0 year-olds(53%). Moreover, the interaction between GrammaticalCategory and Age was also significant (F(2, 45) = 4.424,p = 0.018, ηp2 = 0.164). This interaction reflected thefact that the increase in children’s accuracy over timefor clitic pronouns was greater than that seen for thethird-person plural inflection.
Relationship Between Repetition Tasks andGrammatical Abilities In Italian
To explore the relationship between performance onthe repetition tasks and performance on the grammat-ical tasks, two regression analyses were performed. Toidentify which list is the best predictor of grammaticalabilities, the real-word list was entered as a predictor intoa regression analysis (Table 4) and the non-word list wasentered into a second regression analysis (Table 5). Theoutcome variable (grammatical ability) was computedby averaging the percentage correct for the direct objectclitic pronoun and the third-person plural inflection(the correlation between these two grammar measureswas significant (r = .398 p = 0.005). The first predictorvariable entered into each regression was Age (this was
Real-word and non-word repetition tasks 571
Table 4. Results of the first regression analysis ongrammatical ability
NOTE: R2 total 0.68.aF(2,45) = 4.355 p = 0.018.bF(1,44) = 21.202 p < 0.0001.
a categorical variable, with age 3;0 used as the baselinelevel); the second was repetition performance (real-wordrepetition was entered in the first regression analysis andnon-word repetition in the second).
To assess each regression’s goodness of fit, severalresidual diagnostic plots were performed (using thefunction plot.lm in the software R) (R version 2.8.1).These methods are useful for detecting unusual dataincluding outliers, high/leverage points and influen-tial observations; moreover, they allow us to check thenormality of the residuals (Cook and Weisberg 1982).In particular we calculated the Cook’s distance measure(Cook and Weisberg 1982) on the dependent variable(grammatical ability). Cook’s distance is very usefulfor identifying influential data points. It measures theinfluence of an outlier on both the dependent variable(grammatical ability) and on the set of predictors (real-word list and non-word list). Cook and Weisberg (1982)indicated that a Cook’s distance greater than 1 wouldgenerally be considered large; this provides a “red flag”for identifying outliers (Stevens 1996).
The analysis suggested a satisfactory goodness offit for the two regression models and no outliers weredetected.
A fixed-order multiple regression was first computedto test the contribution of real-word performance to
Table 5. Results of the second regression analysis ongrammatical ability
NOTE: R2 total 0.546.aF(2,45) = 4.355 p = 0.018.bF(1,44) = 37.190 p < 0.0001.
grammatical ability (Table 4). In Step 1, Age explained16.22% of the variance (Sig. F change, p = .018). InStep 2, real-word performance explained 51.78% of thevariance beyond that explained by age (Sig. F changep < .0001) and significantly predicted performance ongrammatical ability (β = 9.608; t = 8.438, p < .0001).
The second fixed-order multiple regression wasconducted to identify the contribution of non-wordperformance to grammatical ability (Table 5). Theresults for Age (Step 1) were the same as in the previousanalysis; in Step 2 the results showed that non-wordperformance explained 38.38% of the variance, beyondthat explained by Age (Sig. F change, p < 0.0001)and significantly predicted performance on grammat-ical ability (β = 7.917; t = 6.098, p < .0001).
English Language
Repetition Tasks
A mixed-design analysis of variance (ANOVA) wascarried out on the percentage of phonemes correct,with Word Type (real-word list and non-word list) andWord Length (two and three syllables) as within-subjectsvariables and Age level (3;0, 3;6, and 4;0 years) asa between-subjects variable. The mean percentage ofphonemes correct and standard deviations for each agegroup are reported in Table 6. The analysis showed amain effect of Age on repetition (F(1, 27) = 3.556,p = .043, ηp2 = .208); however, post-hoc (Bonferroni)testing at the .01 level revealed no significant differencebetween the three age groups. There was also a maineffect of Word Type (F(1, 27) = 5.268, p = .030,ηp2 = .163): children repeated real words (93%) moreaccurately than non-words (91%). No Word Lengtheffect was found.
Table 6. Mean percentage phonemes correct (and standarddeviations) at each word length for real words and non words
As in Italian, performance on the real-wordrepetition and non-word repetition tasks were highlycorrelated (r = 0.708, p < 0.0001).
Grammatical tasks
The mean percentages correct for third-person singularand total past tense (regular and irregular forms) areshown in Table 7 (both third-person singular and totalpast tense were normally distributed: in Kolmogorov-Smirnov test, all ps > 0.05). The percentages correct ofthe total past tense are an average of the percentagescorrect for regular and irregular past tense. Lookingat the irregular past tense column in Table 7, it isimportant to note the different contributions made tothese percentages by correct irregular productions (e.g.,s/he ate) and overregularizations (e.g., s/he eated ). At3;0 years old, 33% of irregular verbs were producedcorrectly (e.g., s/he ate) while 67% were overregular-ized (e.g., s/he eated ); at 3;6, 30% of irregular verbswere produced correctly and 70% were overregularized;finally, at 4;0, 37% were produced correctly and 63%were overregularized. These percentages show that in ourstudy children often treated irregular past tense verbs asregular verbs, using the regular past tense rule.
A mixed-design ANOVA was carried out on thepercentages of correct production with grammaticalcategories (third-person singular and total past tenseinflection) as a within-subjects variable, and age (3;0,3;6 and 4;0 years old) as a between-subjects variable.
The analysis showed a main effect of grammaticalcategories (F(1, 27) = 7.445, p = 0.011, η2 = 0.216)such that third-person singular verbs were producedmore accurately than past tense verbs.
Relationship Between Repetition Tasks andGrammatical Abilities In English Language
Two fixed-order multiple regression analyses wereperformed, the first using performance on the real-words list and the second using performance on the non-words list, to determine which list was the best predictorof grammatical ability (Table 7). In each regressionanalysis the outcome variable was the average of thecorrect productions of the two grammatical morphemes(grammatical ability). The correlation between these two
grammar measures was r = .673, p < 0.0001. Age wasentered as the first predictor variable in both regressions(Age was a categorical variable; 3;0 years was used asbaseline level); repetition performance was entered asthe second predictor in both analyses (real word for thefirst regression analysis and non-word first for the secondanalysis).
Several residual diagnostic plots were first performedto assess goodness of fit for each regression, as wasdone with the Italian data. In this case the two modelspresented a satisfactory goodness of fit and no outlierswere detected (Cook and Weisberg 1982).
The first regression was computed to test thecontribution of real-word performance to grammati-cal ability (Table 8). In Step 1, age explained 9.44% ofvariance (Sig. F change, p = n.s.). In Step 2 real wordsexplained 4.5% of the variance beyond that explainedby age (Sig. F change p = n.s.).
The second regression was conducted to identifythe contribution of non-word performance (Table 9).In Step 1, age explained 9.44% of the variance (Sig. Fchange p = n.s.). In Step 2 the non-word lists explained22.26% of the variance beyond that explained by age(Sig. F change p = .008) and significantly predictedperformance on the grammatical ability tasks (β =1.8327; t = 3.285, p = .003).
Comparison Between the Two Languages
So far, we have assessed the relationship betweenrepetition ability and grammatical ability within each of
Table 8. Results of the first regression analysis ongrammatical ability
NOTE: R2 total 0.357.aF(2,27) = 1.401 p = 0.262.bF(1,26) = 10.614 p = 0.003.
the two languages. The results supported two differentmodels: for the Italian data, performance on the real-word repetition task explained more of the variance(51.78% beyond that explained by age) in grammaticalability than performance on the non-word repetitiontask did (38.38% beyond that explained by age); ageexplained 16.22% of the variance. In contrast, for theEnglish data, performance on non-word repetition tasksexplained more variance (22.26% beyond that explainedby age) in grammatical ability than performance onthe real-word repetition tasks did (4.5% beyond thatexplained by age); age explained 9.44% of the variance.
In this last section we explore whether there arecross-linguistic differences by directly comparing thereal-word performance for Italian and English and non-word performance for both languages. The aim of thiscomparison is to better understand the importance ofa given repetition task (e.g., real-word) in the twolanguages; only this kind of analysis can clarify the roleof language-specific characteristics in the relationshipbetween repetition tasks and grammatical ability. Even
though the dependent variable (grammatical ability)is based on different set of morphemes in Italian andEnglish, the comparison is theoretically and empiricallymotivated because each set constitutes a clinical markerin the respective language.
In order to test these differences we followed threesteps. The example here compares Italian and Englishreal words, but the same method was used to compareItalian and English non-words:
1 In the first step the effect of Age was excludedboth from Italian Grammatical Ability andEnglish Grammatical Ability. We named theseItalian Grammatical Ability Residual Adjusted forAge and English Grammatical Ability ResidualAdjusted for Age (see Figure 1Grammatical AbilityResidual Adjusted for Age).
2 The correlation between Italian GrammaticalAbility Residual Adjusted for Age and Italianreal-word repetition was calculated; separately,the correlation between English GrammaticalAbility Residual Adjusted for Age and Englishreal-word performance was calculated.
3 These two correlations were compared using theTest of Difference Between Two IndependentCorrelations (Cohen and Cohen, 1983).
The results showed that there were not signifi-cant differences between the two languages in therelationship between grammatical ability and non-wordrepetition, whereas there were significant differences inthe relationship between grammatical ability and real-word repetition (Figure 1).
Figure 1. Comparison between Italian and English language. The p value was obtained using the Test of Difference Between Two IndependentCorrelations (Itaian sample n = 48, English sample n = 30). The square of each single correlation is equivalent to the proportion of the totalvariance of Grammar accounted for by Word Type after adjusting for Age (see R2-change in Table 4,5,8,9).
574 M. Dispaldro et al.
Discussion and Conclusion
The main aim of this study was to investigate thepossible cross-linguistic differences between real-wordand non-word repetition in their potential to predictgrammatical ability. A group of Italian monolingual anda group of English monolingual children were selected.Both groups were composed of three-to four-year-oldchildren with typical language development. Each childwas administered two repetition tasks and two taskstesting grammatical ability.
For both the Italian and the English groups,children’s performance confirmed what was alreadyknown from previous studies: real words are easierto repeat than non-words (Chiat and Roy 2007,Dispaldro et al . 2009). Also, for both groups, children’sgrammatical performance confirmed that they weredeveloping language in a typical fashion. (Leonardet al . 2002, Rice and Wexler, 1996, Conti-Ramsdenet al . 2001). Contrary to expectations, we did not finda syllable length effect in English non-word repetition(whereas, in Italian it was evident). We interpret thisresult with caution and note some possibly relevantaspects of the study that may have led to this finding.The first has to do with the well known fact thatlong-term language knowledge facilitates repetitionaccuracy; for example, children repeat non-wordsmore accurately when the stressed syllable is a realword (e.g., bathesis -bath) than when it is not a realword (fathesis) (Dollaghan et al. 1993). Many of Royand Chiat’s non-words contain or are very similarto real English words and some of these are familiarto children (“jamic” /ˈdƷæ mɪk/ : [“jam”/ˈdƷæ m/];“lodihay”/ˈlɑd@he/ : [“hay”/ˈheɪ/]; “serpen” /ˈsɝpn/ :[“serpent” / ˈsɜp@;nt/]; “sinodaur” /ˈsaɪnɅdɔɹ/ :[“sign”/ˈsaɪn/]; “shameen”/ʃɅ ˈmin/ : [“mean”/ˈmin/];“gazameen” /gæ zɅˈmin/ :[“mean”/ˈmin/]; “rigasette” /rɪgɅ sεt/ : [“set” /ˈsεt/]). Lexical support during non-word repetition could have facilitated the performanceof the English-speaking children, but it should haveimproved non-word performance overall, leaving anylength effect intact. On the other hand, this overallimprovement may have raised children’s scores toceiling so that differences related to syllable length werenot detectable.
Another reason that a length effect was not evidentfor English non-words could be the small sample size.In a small group, individual performance can have agreater impact on group means. Despite the fact thatwe found no statistical outliers, there were childrenwho performed at ceiling on non-word repetition.In a small group, these children’s performance couldhave minimized the difference between two and threesyllables non-words. Perhaps the length effect could onlybe shown with more power.
Regarding the relationship between repetitiontasks and grammatical ability, there were two mainresults:
1. A cross-linguistic comparison showed that inboth Italian and English, non-word repetitionsignificantly predicted grammatical ability.
2. Performance on real-word repetition predictedchildren’s grammatical ability in Italian butnot in English; in particular, in Italian, real-word repetition explained children’s grammat-ical ability better than non-word repetition.
Addressing first the predictive power of non-wordrepetition as a function of language spoken, our resultsshowed that non-word repetition predicted grammat-ical ability in both languages. Based on considera-tion of the different characteristics of grammaticalmorphology in the two languages, we had suspectedthat non-word repetition would be more predictive ofgrammar in English than in Italian. That is, successin learning English morphology would appear to rely,to a greater extent than Italian, on the ability toencode and retain small and infrequent phonologicaldifferences in words. Although not the only contributorsto non-word repetition ability, phonological processingand storage are considered to be central to this task(Gathercole 2006). In Italian, inflectional morphologyis more salient and varied phonologically as well as moretied to meaning; thus, the relationship between non-word repetition and grammar might not be as strong.Although cross-linguistic differences in the strength ofnon-word repetition as a predictor of grammar werenot borne out, the presence of a significant relation-ship in each language suggests that the abilities underly-ing non-word repetition play an important role in thedevelopment of children’s grammatical abilities, at leastfor children with typical language.
Our second main result addresses the relationshipbetween grammatical ability and real word repetition.In English, this relationship was not significant; inItalian, the two abilities were more strongly related thanwere non-word repetition and grammar. The fact thatwe found a significant relationship in Italian but notin English is consistent with differences in the natureof grammatical morphology in the two languages. InItalian, unlike in English, grammatical morphology ispervasive and carries significant meaning; for example,because Italian does not require overt subject pronouns,the referent of the verb’s subject must be recovered fromthe person, number, and gender marking on the verb.Thus, it would not be surprising that lexical knowledge(as indexed by real-word repetition) and grammaticalability would be closely intertwined in Italian.
Differences in the relationship between lexicaland grammatical knowledge have been observed inprevious work on children acquiring English and Italian(Caselli et al . 1999, Devescovi et al . 2005). Whilevocabulary and grammar have been found to be stronglyrelated during acquisition in both languages (Batesand Goodman 1999), there are also cross-linguisticdifferences. Caselli et al . (1999) found a linear relation-ship in Italian between function words and vocabularysize; function words appeared early and increased at asteady rate, as a function of a vocabulary size. In contrast,for English, they found that this relationship was non-linear; the rate of increase in the proportion of functionwords remained flat until vocabulary size reached about400 words and only then began to increase. In anotherstudy, Devescovi et al . (2005) looked at the relation-ship between syntactic complexity, quantified by varioustypes of utterance length measures, and vocabulary size.They also found non-linear components in this relation-ship for English but not for Italian. For Italian, syntacticcomplexity developed early and increased steadily withvocabulary size, whereas in English, syntactic complexitylagged behind vocabulary growth.
Relating these findings to our own study, iflexical and grammatical knowledge are more closelylinked in development for Italian speaking childrenthan for English speaking children, then we mightexpect real-word repetition (insofar as it indexes lexicalknowledge) to have a closer relationship to grammati-cal measures. Devescovi et al . (2005) suggested that thistighter relationship between vocabulary and grammar inItalian was due to characteristics of Italian grammaticalmorphology. Specifically, Italian is a system that provides“a large but consistent set of regularities”, requiring lessinput in order for the learner to abstract generaliza-tions. For English on the other hand, fewer exemplars ofthe targeted grammatical elements might lead to slowerlearning.
Although our findings on real word repetition andgrammar ability are consistent with this understand-ing of language learning and cross-linguistic differences,we must be cautious. For example, we cannot excludethe possibility that the lack of significant relation-ship between real word repetition and grammar forEnglish was not due to differences between the Italianand English real-word stimuli relating to differencesin Age of Acquisition. The words contained in theItalian real-word list were used in a previous study(Dispaldro et al. 2009); the authors showed that themajority of these words were already known by the 3and 4 year-old children. Moreover, according to theItalian MacArthur database (Caselli et al . 2007) ‘nebbia’[fog], ‘tamburo’ [drum] and ‘torre’ [tower] are acquiredrespectively at 33 months, 29 months, and 28 months.Age of Acquisition was not a criterion in the selectionof the English real words, but we presume that some
of these words are acquired before three years of age.Consequently, it is possible that English real-words werehighly familiar even to the youngest age group, leading toa ceiling effect: whereas, for Italian, real word repetitionconsistently improves across age groups, for English,performance in the 3;6 group is already close to ceiling.The failure for English real-words to predict grammati-cal competence may be due to these ceiling effects.
The findings of our study also have implications forgenetics research. Bishop et al. (2006) have discoveredthat some of the abilities examined in this study (non-word repetition ability, grammatical ability) appear tohave a genetic basis. However, given the cross-linguisticdifferences observed, a given ability may prove to beless, or more, important depending on the propertiesof the language being learned. For example, it could bethe case that an ability reflected in real-word repetitiontasks is heritable in all children. However, in languagessuch as Italian, this ability might serve as a predictorof grammatical ability whereas in a language such asEnglish, this ability may not have the same predictivevalue.
These possibilities raise an interesting questionabout how phenotypes should be treated acrosslanguages. One possibility is to treat them in the mannerin which they have just been discussed, namely, asuniversal abilities whose relevance to grammatical abilitywill have to be determined on a language-by-languagebasis. Another possibility is to treat the particularlanguage being learned as an additional predictor, alongwith the phenotype. Here, language might be regardedas an environmental predictor, much as measures suchas maternal education level are used. In this case, thequestion is how much variance in grammatical abilitycan be explained by the phenotype when the particularlanguage being learned is also included in the model.
Finally, the results of this study also have clinicalrelevance. Many researchers have argued that therepetition task is a simple and practical tool that can bescored online and easily adapted to the clinic environ-ment. However, our study suggests that the best choiceof target in this task (real-word vs. non-word) coulddepend on the specific language spoken by the child.Non-words have been considered the best type of targetgiven that numerous studies have shown that it is asensitive test of language impairment (Bortolini et al .2006, Conti-Ramsden et al . 2001). While this is true,our study has shown that there may be different “bestpredictors” for Italian and English. This finding isvery important in that it could allow us to maximizepredictive power in each language.
References
BARCA, L., BURANI, C. and ARDUINO, L. S., 2002, Word namingtimes and psycholinguistic norms for Italian nouns. BehaviorResearch Methods, Instruments, & Computers, 34 (3), 424–434.
BATES, E. and GOODMAN, J. C., 1999, On the Emergence of Grammarfrom the Lexicon. In B. MacWhinney (eds), The Emergenceof Language. Mahaw, NJ: Erlbaum.
BISHOP, D. V. M., ADAMS, C. V. and NORBURY, C. F., 2006,Distinct genetic influences on grammar and phonologicalshort-term memory deficits: Evidence from 6-year-old twins.Genes, Brain and Behavior, 5, 158–169.
BORTOLINI, U., ARFE, B., CASELLI, M. C., DEGASPERI, L., DEEVY,P. and LEONARD, L. B., 2006, Clinical markers for specificlanguage impairment in Italian: the contribution of cliticsand non-word repetition. International Journal of Languageand Communication Disorders, 41 (6), 695–712.
BOTTING, N. and CONTI-RAMSDEN, G., 2001, Non-word repetitionand language development in children with specific languageimpairment (SLI). International Journal of Language andCommunication Disorders, 36 (4), 421–432.
CASELLI, M. C., CASADIO, P. and BATES, E., 1999, A comparisonof the transition from first words to grammar in English andItalian. Journal of Child Language, 26, 69–111.
CASELLI, M. C., STEFANINI, S. and PASQUALETTI, P., 2007, Parole efrasi nel “Primo vocabolario del bambino”. Nuovi dati normativifra i 18 ed i 36 mesi e forma breve del questionario. Milano:Franco Angeli.
CHIAT, S. and ROY, P., 2007, The preschool repetition test:An evaluation of performance in typically developing andclinically referred children. Journal of Speech, Language andHearing Research, 50, 429–443.
COADY, J. A. and EVANS, J. L., 2008, Uses and interpretations of non-word repetition tasks in children with and without specificlanguage impairment (SLI). International Journal of Languageand Communication Disorders, 43 (1), 1–40.
COHEN, J. and COHEN, P., 1983, Applied Multiple Regression/Correlation Analysis for the Behavioral Sciences. Hillsdale, NJ:Erlbaum.
CONTI-RAMSDEN, G., BOTTING, N. and FARAGHER, B., 2001,Psycholinguistic markers for specific language impairment.Journal of Child Psychology and Psychiatry, 42 (6), 741–748.
COOK, R. D. and WEISBERG, S., 1982, Residuals and Influence inRegression. London: Chapman and Hall.
DEVESCOVI, A., CASELLI, M. C., MARCHIONE, D., PASQUALETTI, P.,REILLY, J. and BATES, E., 2005, A crosslinguistic study ofthe relationship between grammar and lexical development.Journal of Child Language, 32, 759–786.
DISPALDRO, M., BENELLI, B., MARCOLINI, S. and STELLA, G.,2009, Real word repetition as a predictor of grammat-ical competence in Italian children. International Journalof Language and Communication Disorders, 44 (6), 941–961.
DOLLAGHAN, C. A., BIBER, M. E. and CAMPBELL, T. F., 1993, Lexical
influence on non-word repetition. Applied Psycholinguistics,16 (2), 211–222.
DOLLAGHAN, C. and CAMPBELL, T. F., 1998, Nonword repetitionand child language impairment. Journal of Speech, Language,and Hearing Research, 41, 1136–1146.
EDWARDS, J., BECKMAN, M. E. and MUNSON, B., 2004, The interac-tion between vocabulary size and phonotactic probabilityeffects on children’s production accuracy and fluency in non-word repetition. Journal of Speech, Language, and HearingResearch, 47, 421–436.
GATHERCOLE, S. E., 1995, Is non-word repetition a test of phonolog-ical memory or long-term knowledge? It all depends on thenon-words. Memory & Cognition, 23 (1), 83–94.
GATHERCOLE, S. E., 2006, Non-word repetition and word learning:The nature of the relationship. Applied Psycholinguistics, 27(4), 513–544.
GATHERCOLE, S. E., WILLIS, C., EMSLIE, H. and BADDELEY, A. D.,1994, The children’s Test of non-word repetition: a test ofphonological working memory. Memory, 2, 103–127.
LEONARD, L. B., CASELLI, M. C. and DEVESCOVI, A., 2002, Italianchildren’s use of verb and noun morphology during thepreschool years. First Language, 22, 287–304.
MARCUS, G., PINKER, S., ULLMAN, M., HOLLANDER, M., ROSEN, T.J.E XU, F., 1992, Overregularization in language acquisition.Monographs of the Society for Research in Child Development,57(4), 228
MUNSON, B., KURTZ, B., and WINDSOR, J., 2005, The influenceof vocabulary size, phonotactic probability, and wordlikenesson nonword repetitions of children with and without specificlanguage impairment. Journal of Speech, Language and HearingResearch, 48, 1033–1047.
RADFORD, A., 2004, Minimalist Syntax: Exploring the Structure ofEnglish, Cambridge: Cambridge University Press.
REYNELL, J. K. and GRUBER, C. P., 1990, Reynell DevelopmentalLanguage Scales. Los Angeles: Western Psychological Service.
RICE, M. and WEXLER, K., 1996, Toward tense as a clinical markerof specific language impairment in English-speaking children.Journal of Speech and Hearing Research, 39, 1239–1257.
RICE, M. and WEXLER, K., 2001, Test of Early GrammaticalImpairment. San Antonio, TX: The Psychological Corpora-tion.
ROY, P. and CHIAT, S., 2004, A prosodically controlled word andnonword repetition task for 2-to 4-year-olds: evidence fromtypically developing children. Journal of Speech and HearingResearch, 42, 223–234.
SCALISE, S., 1994, Morfologia, Bologna: Il Mulino.STEVENS, J. P., 1996, Applied Multivariate Statistics for the Social
Sciences, Mahwah, New Jersey: Lawrence Erlbaum Associates.TRIFONE, P. and PALERMO, M., 2000, Grammatica Italiana di Base,
Appendix B: English Real-word and Non-word Lists (adapted from Chiat and Roy, 2007)
Syl labl e
Lengh tReal Words Non-Words
2 / m d / / d m k/
3 / h l de/ / l d e/
3 /b n n / /n n b /
2 / læ d / / dæ l /
2 / p sn/ / s pn/
3 / d n s r/ / s n d /
2 /p lis/ /l pis/
3 /k m pju dr/ /t kju pr/
2 /m in/ / min/
3 /s g r t/ /r g s t/
3 /m g zin/ /g z min/
2 /b lun/ /l bun/
578 M. Dispaldro et al.
Appendix C: Italian Grammatical Task: Third person plural inflection in the indicative presenttense verbs.
BEVONO THEY DRINKDORMONO THEY SLEEPtelefona she phonesscrive he writesTELEFONANO THEY PHONEpiange she criesSCRIVONO THEY WRITECORRONO THEY RUNPIANGONO THEY CRYSALGONO THEY GO UPdorme she sleepscorre she runssale she goes upmangia she eatscanta she singsbeve she drinksMANGIANO THEY EATCANTANO THEY SING
Appendix D: Italian Grammatical Task: Third person of direct object clitic pronouns.
I bambini lavano i piatti e poi. .LI asciugano. The boys wash the plates and then. .they wipe them.Le bambine comprano il gelato e poi. .LO mangiano. The girls buy the ice-cream and then. .they eat it.Il bambino lava la macchina e poi. .LA spinge. The boy washes the car and then. .he pushes it.I bambini raccolgono le mele e poi. .LE mangiano. The boys pick the apples and then. .they eat them.La bambina lava la macchina e poi. .LA spinge. The girl washes the car and then. .she pushes it.Le bambine lavano i piatti e poi. .LI asciugano. The girls wash the plates and then. .they wipe them.La bambina raccoglie le mele e poi. .LE mangia. The girl picks up the apples and then. .she eats them.Il bambino compra il gelato e poi . .LO mangia. The boy buys the ice cream and then. .he eats it.Le bambine lavano la macchina e poi. .LA spingono. The girls wash the car and then. .they push it.Il bambino raccoglie le mele e poi. .LE mangia. The boy picks the apples and then. .he eats them.Il bambino lava i piatti e poi. .LI asciuga. The boy washes the plats and then. .he wipes them.La bambina compra il gelato e poi. .LO mangia. The girl buys the ice cream and then. .she eats it.Le bambine raccolgono le mele e poi. .LE mangiano. The girls pick up the apples and then. .they eat them.La bambina lava i piatti e poi. .LI asciuga. The girl washes the plates and then. .she wipes them.I bambini lavano la macchina e poi. .LA spingono. The boys wash the car and then. .they push it.I bambini comprano il gelato e poi. .LO mangiano. The boys buy the ice cream and then. .they eat it.
