Inseparabilidad de la gramtática y el léxico en adquisición del lenguaje.pdf

8/12/2019 Inseparabilidad de la gramttica y el lxico en adquisicin del lenguaje.pdf

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Essential Readings in evelopmental PsychologySeriesEditors:AlanSlaterandDarwinMuir

Queers University. Kingston, Ontario and the University of ExeterIn thisbrand new series of nine books, Alan Slater and D arwin Muir, together with a teamof expert editors. bring together selections ofreadings illustrating important methodologi-cal, empirical and theoretical issues in the reaof developm ental psychology. Volumes inthe series an d their editors aredetailed below:

Language DevelopmentTheEssentialReadings

Editedby Michael Tomasello an dElizabeth Bates

InfantDevelopmentChildhoodSocial DevelopmentChildhood CognitiveDevelopmentAdolescent DevelopmentThe PsychologyofAgingThe Nature/NurtureDebateTeaching andLearningLanguage DevelopmentChildren and the Law

DarwinMuirand Alan SlaterWendy CraigKang LeeGemidAdamsWilliam GekoskiSteven Ceciand Wendy WilliamsCharles Desforges and Richard FoxMichael Tomaselloand ElizabethBatesRay Bull

Eachof the books is introduced by the volume editor with a rationale behind the chosenpapers. Each reading is then introduced and contextualised with-in the in dividual subjectdebate as well as within the wider context ofdevelopmental psychology. Aselection offurther reading is also assigned, making each volume an ideal teaching resourcefor bothclassroom an dindividual study settngs.

LACKWELL


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Onthe InseparabilityofGrammarand theLexicn:EvidencefromAcquisitionElzabeth E3rteg>and Judth C.Goodman

Linguisticsis afieldth at is know n for controversy. However,onegeneral trend has char-acterizedrecentproposals inotherwisevery diverse theoretical frameworks: more andmoreof the explanatory work thatwaspreviously handled by thegrammarhas beenmoved intothe lexicn. In some frameworks (e.g.,Chomsky, 1981. 1995), the gram-maticalcomponent that remainsis an austere, "stripped down" system characterizedbyasingle ruleformovement and a set ofconstraintson the application ofthat rule.In thistheory, therichnessanddiversityoflinguisticformswithin any particular lan-guage are now captured almost entirelyby thelexicn- although thisis now averycomplex lexicnthatincludespropositional structures andproductivarules thatgovernthe way elements arecombined. Thetrendtoward lexicalism iseven moreapparentinalternative frameworks likeLexical Functional Grammar (Bresnan, 2001) andHead-Driven PhraseStructureGrammar(Pollard&Sag, 1994).Itreachesitslogical conclu-sin in a framework called Construction Grammar (Fillmoreet al., 1988: Goldberg,1995) ,inwhichthedistinction between grammarand thelexicnhasdisappearedalto-gether (seealso Langacker, 1987). Instead.allelementsof linguistic form are repre-sentedwithinaheterogeneouslexicnthatcontainsboundmorphemes, free-standingcontenandfun ction words,andcomplex phrase structures w thout terminal elements(e.g., the passive). This lexicn can be likenedto a large municipal zoo. with manydifferent kindsofanimis.To besure,theanimis varygreatlyinsize, shape, food pref-erence, lifestyle, and the kind of handling they require. But they live together inon ecompound. under common management. The new lexicalist perspectve is quitedifferent from the modular proposals that characterized the first two decades or soof modern generative linguistics, which postulatedseprate bu t roughlyequalcom-ponents fo r semantics (includinglexical description). grammar. an d phonology (e.g.,Chomsky.1965).The field of language acquisition has (with some exceptions) not kept up with thislexicalist movement in l inguist ic theory. Many nvestigators wi th in the field are stillfirmlyrooted in the modular perspective that characterized linguistic theory th i r ty* Redacled from Langutuie and Cogiiilive Processes. 1997 . 2 I 5 / 6 ) , 507-584.

On the Inseparability of Grammarand the Lexicn 735years ago, seekingadiscrete an ddiscontinuous boundary between gramm ar and (helexicn, and/or between those lexical tems that do grammatical work andthose tha tdo not(e.g.,thedistinc tion betweenclosed-andopen-class words- Garretl . 1992:thecontrast between regularand irregular morphology- Pinker, 1991).Inthis paper.wewill review evidence on the relationshipbetween lexical developmenl and the emer-gcnceo fg ramm ar tha t suppor ts a unified lexicalist view.

We willbegin with evidenceon theperiod between8 and 30months, when childrenmakethepassage fromfirstwordsto grammar, showing thatthe emergence andelab-oration ofg r a m m a rare highlydependen upon vocabularysize.Then wewillcomparethese results for normal children with studies ofearlylanguagedevelopmentin severalatypical populations, includingearlytalkers, children withfocal brain injury,WilliamsSyndrome.a ndDown Syndrome. Resultswillshow that (a)g r a m m a ra ndvocabularydo no t dissociatein early talkers or in children with focalbrain injury, at least no twithin thisphaseofdevelopment,( b)grammatical development neveroutstripslexicalgrowth, evenn the Williamspopulation(aform ofretardationinwhichlinguisticabil-itiesaresurprisingly sparedin theadul tsteadystate),and (c)grammatical developmentcan fall behind vocabulary insomesubgroups (e.g.,Down Syndrome). but this appar-ent dissociation can be explained by limits on auditory processing. We conc lude th atth ecasefo r amodula rdistinctionbetween grammarand thelexicninlangua ge devel-opmenthas beenoverstated (seealsoMacDonaldetal.,1994),and that developmen-talevidence is more compatible with a radically lexicalist theory of gram mar(GoWberg,1995;MacWhinney, 1993) .Thisdoes not mean that grammatical structures don't exist (they do),or that therepresentations that underlie grammatical phenomena are identical to those thatunderle single-content words (they are not). Rather, we are suggesting that theheterogeneous set of linguistic formsthatoccur in anynatural language (.e.. words,morphemes,phrase structure types)may be acqured and processed by a unified pro-cessing system, one that obeys a common set of activation and le arnin g principies.Thereis noneedf ordiscontinuous boundaries.

I. Grammarand theLexicnin NormallyDeveloping ChildrenAffirstglance,th e course ofearly languag e development seemst oprovideaprimafaciecase forlinguisticmodularity. Children begin their linguisticcareerswith babble. start-ng with vowels (somewhere around 3-4 months.on average)and ending withcom-binations of vowels and consonants of increasing complexity (usually between 6 and12 months) .Meaningful speech emerges some time between 10 and 12 months, onaverage, although wordcomprehensionmay b egin a fewweeksearlier.After this, mostchildrenspendmany weeksormonths producing single-word utterances.At firsttheirrateo fvocab ulary growth isvery slow. but one typicallysees a "burst"or accelerationintherateofvocabulary growth somewherebetween16 and 20 months. First wordcombinations usually appear between 18 and 20 months. a l t houghthey tend to berather spare and telegraphic (at least in Knglish). Somewhere between 24 and 30months. most children show a kind of "second burst."a flowering of morphosyntaxthat RogerBrown ( 1 9 7 3 )h as characterizedas"theivycomingi nbetween th ebricks."


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Introduction to Word Learn'mqTable 10 1 Reiations betweengrammatical development an d voeabulary size from 20 to 28months (From Bateset al ., 1988)

20-monthvocabulary20-monthMLU'28-monthvocabulary28-monthMLU 1

20-monthvocabulary

+.54"+.64"+.83**

20-month 28-month 28-monthMLU 1 vocabulary MLU1

+.47*+.48* +.73**

* p < . ( ) 5** p < . 0 11 Mean length ofutterancei nmorphemes.

lary sizewa s assessed with a combination of video observations and parental report.Grammatical developmentw asassessed in astandard fash ion, calculatingmeanlengthof utterance in morphemes (MLU) from speech transcriptions,following the rulesout-lined by Brown (1973) .2 Table 10.1 summarizes the cross-lag correlations that wefound between lexicalan d grammatical development withinandacrossthese two agelevis. Results were very clear: The single best estimate of grammatical status at 28months (right in the heart of the "grammar burst") is total vocabulary size at 20months (measured right in the middleof the "vocabulary burst"). In fac, the correla-tion coefflcient in this and related analyses with other grammatical variables hoveredconsistently between+.70 and+.84.Because weknow thatnomeasurecan correlatewithanothervariable higher thanit correlates w ith itself (i.e., Spearman's Law ofReli-ability),it isinterestingtonote that sepratesamplesof MLU at 28monthsof agealsotendto intercorrelate in the+.75h.80range. Whatthismeans,inessence, isthat 20 -month vocabulary and 28-monthM LUscoresa re statistically identical; one could beused as a stand-in for the other in predicting a child's rank within his/hergr oup. Ofcourse this kind of correlational finding does not forc us to conclude that grammaran dvocabulary growth ar e mediatedb y the same developmental mechanism. Correla-tion is not cause. At the very least. however. this powerful correlation suggests that thetw o have something important in common.In a more recent series of studies,w e have developed a newparental report instru-mentcal led the Ma cArt hur Communicative Development Inventory( CD I ) to study therelationship betweenlexical an d grammatical developmenti n amuch larger sampleof1,800normally developing children,primarily middleclass,a ll growingup inKnglish-speaking households (Fenson et al .. J994). Th e CDI reliesprimarily on a checklisttormat to assess word comprehension (from 8-16 month s). word production (from

On the Inseparab ility of Grammar and the Lexicn 1398-30 months). and the emergence of gramm ar (from 16-30 months).Details con-cerningthesetwo Instrument s ( inKnglisha nd Ral lan) are provided inCasclliet al.(thisvolume).For our purposes here,the most important aspects of this instrument are thevocabularychecklist (containing6 80 wordson the Words and FhrasesScale.intendedfo r 16-30-month-olds) , and the grammatical complexity checklist. The complexitychecklistcontains.37sentence pairs. each relectingasingle linguisticcontrast thatisknown to come in during this agerangc(e.g.. "KITTYSLEEPINU"pairedwith "KITTYISSLliEPINC").P arents wereasked to indcate(eveni ftheirchild had not said thispar-ticular sentence) which sentence in each pair"soundsmorelikethe way thatyourchildista lking right now."Additional Information about grammar comes from a secondinwhich parents writeout thethree longest sentences that theycanremember theirchildsaying in the last couple of weeks (on the grounds that these would be sufficientlyrecent and striking events tohave some validity evenin recallmode).Finally, wepro-vided a list of irregular nouns and verbs in their correct inflected forras (e.g., teeth;made), as well as a list of regularization errors that are common in young Knglish-speaking children(e.g.,tooths; maked). Parents were asked tocheck whether they hadheard their child producea nyo f these forms.These threedifferent modeso f assessingearly grammar were all highly correlated in the Fensonet al.study. More importantlystill.t hethreemeasures correlate very hig hly with traditional laboratory measures ofgrammaticalcomplexity (D ale. 1991; Dale et al., 1989), including correlations withMLUup to the statistical ceiling(i.e..a s high asM LUcorrelates with itself in reliabilitystudies).It isthusfairt oconcludethat these measuresconstitute avalid andreliableestimateo f individualdifferences ingrammatical development across the period from16-30 month s of age. In most of the results that follow. wewill concntrate on therelation between vocabularysize and g ramm ar using the 3 7-item gramm atical com-plexity scale as our primary outcome variable. It isclear from the validation studies.however. that any of these parent report and/or laboratoryestmalesof gross progressin grammar wouldyield the same result.As reported byFenson et al. (1994), the relationship between gramma tical com-plexityand v ocabulary size in theirlargecross-sectional sample replicates and extendsthe powerful gramm ar/voca bulary relationship thath ademergedinBateset al.(1988).Figure 10.2 (from Fenson et al.)Ilstrales the relation between performance on the3 7-item s entenc e complexity scale and productive vocabulary size (collapsed overage, with children divided into groups reflecting fewer than 50 words, 50-100words,101-200words.201-300words. 301-400words.401-500words, 501-600words an d >600words).Th e linear correlation between these tw o measures is +.84(p


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14O Introduccin to Word Learnii

So.o

toE2C3

600Vocabularysize

Figure 10 2 Mean an d s tandard errors for grammatical complexity inchildren at differentvocabu lary levis.

ciation between word Comprehension and word production observed at an earlierpoint in language developmcnt. Figure10.3bdisplays the relation between expressivevocabulary (on the vertical axis) an d receptve vocabulary (on the horizontal axis),collapsed over age in children between 8 and 16months (redrawn from the MacArthurnorming study,Fenson etal.,1994).Analogo us to figure10.3a.figure10.3bIlstralesth e relation between domains by plotting scores at the90th, 75th. 50th. 25 t h , an dlOth percentile for word production within each Comprehension group. What we seein figure 10.3 b is a classic fan-shaped pattern of varation. in clud ing children wh o arestillproducing virtuallyno meaningfulspeech at all despte receptive vocabularies ofmore than 200 words. Henee this figure captures aphenomenon that iswell attestedin the child language literature: Comprehension and production can dissociate to aremarkabledegree. A certain level of word Comprehension isprerequisite for expres-sive language to get off the ground. bu t Comprehension ( though necessary) is appar-entlyn ot sufficient. If th esamet h ngwere truefor therelationship between vocabularyand grammar, wewould expect the samekind of fan-shapedvariancein figure10.3a.Thats. we mightexpect vocab ulary sizetoplaceaceilingongrammat ica ldevelopmentup to somewhere between 50 and 200 words (when most children make the passageinto m ultiword speech).After that point. th e variance should spread outward as the

tw odomains decoupleand g r a mma r takesoff on its ow ncourse. Instead.we tndt ha tgrammar and vocabulary are tghtly coupled acrosst he 16-30-monthage range.

o.o

E2C5

600

-o


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744 Introduccin to Word Learnina

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146 Introduccin to Word Learning

Stem+corredirregular

O 1-9 10-1920-2930-3940-4950-5960-6970-7980-8990-99100+Sizeofverb vocabularyFigure10 8 Reportedproduction of16 irregularverbsas afunctiono fvocabulary size (fromMarchman& Bates.1994).approach(Brown. 1973;Marcusetal.,1992;Pinker,1991).Connectionist simulationsof the acquisition of past-tense morphology have shown that a single mechanismcan displaymany of the same behaviors that characterize grammatical learning inchildren. These includean init ialstage inwhich the systemproduces high-frequencyirregularpast-tenseformscorrectly(e.g., CAME,WENT),alengthy intermedatephasem which thesecorredformscoexistwithoccasional overregularizations(e.g.,COMED.GOED).followedby anasymptotic convergenceon the use of correctregularsand irreg-ulars.However. as criticsof the single-mechanism account have noted (e.g., Marcusetal.,1992), thesechangesare linkedto the sizeandcompositionof verb vocabulary(e.g..high-frequency irregulars tendtodomna tein theearlystages;theappearanceofoverregularizationscorrelates with an increasein theproportionof regularstoirre-gularsin thenetworks "vocabulary"). Thisraisesan importantquestion:is past-tenselearninginrealchldren alsotiedtochanges in vocabularysize?Figure 10.8from M archman and Bates iliustrates the relation between numb er ofverbs in the childs voca bulary (basedon thesubsetof verbs that are used in the vocabu-

larychecklist and n thepast-ten se scale)a ndthree forms of past-tense marking-xerostem (thechild isreportedt ousethe verb in thedtation form only).correct irregula rs

Ont he Inseparability of Grsmmar and the Lexicn 147and ncorrect overgeneralizations. This figurereveis a strong n onlin earrelatonshipbetween verb vocabulary size and successive phases in the developrnent of past-tensemorphemes. s imila rto the relationship observed inconnectionist s imulations of thislearning process.This demonstration of a l ink belween verbvocabulary and past- tense morphologyisthe only example we have right now of a linkbetween specificgrammatica lstruc-tures andtheirrequisite "criticalmass"o f lexicaltems. A great dealmoreworkcouldbe done n thisrea, to de te rminethe lexicalprerequisites (if any)fo r specific gram-matical forms. whichm ayvarysubstantiallywithin andacross langu ages.Fo rnow.weturn to adifferent set ofquestions.I st he powerful grammar-vocabularyrelationshipuniversal foranyoneacquiring English.or can wetind atypical popula t ionsin whichdissociations between lexicaland grammatical developrnentareobserved?

II. Grammatical Developmen tand theLexicnnAtypical PopulationsAlthough g rammatical developrnent invariablyfollows a stage in which single wordsareacquired, the findings reviewedso far suggest that, aside from this temporal lag.thereis no dissociation between grammar and lexical developmentin normal children.In view of the claims thathave been mad e about the dissociabilityof these dom ains inadults. it seemed important to us to determine whether there are any individualchildren or anyspecific pediatric populations wh odeviatefrom th e functiondisplayedinfigures10.2-10.6.In fact. the literatureon older children with language disorders givesusreasontoexpect selective impairments inearly grammar.Specific Language Impairmentor SLIisdefinedas adelayinexpressive languageabilitiesthatis at least 1stand ard deviationbelow the meanfor the child'schronological age.in theabsenceo fmen tal retardation,frank neurological imp airme nt. social-emotional disorders(e.g.,aut ism) ,or anyotherseriousbiomedical riskfactorsthatcouldaccountforthedelay. Althoug hthedefinitionof SLI presupposesthat language can be dissociated from the rest of cognition, thespeciicityofSpecificLanguage Impairmentis stillcontroversial(Bishop,1997;Gopnik.1990: Leonard, 1998). For example. many investigators report that children with SLIscore significantly below age-matched co ntrols on at least some nonling uistic mea-sures, inclu ding mental imagery. symbolic play. shifting attention. and the ability todetect rapid temporal changesin aud itory stimuli (see Bishop and Leonard for reviews).There is considerably more agreementabout thenatureof the language impairmentin SLI. Withinevery linguisticdomain that has been studied to date, the expressiveand/or receptive abilities of children with SLI are qualitatively similar to those ofyounger norm al children. but delaysseemto be greater for grammar.The vulnerability ofgrammarin SLI has ledto some radicalproposals.For example.Gopnik(1990)and Pinker (1991)described afamily with what appearedto be acon-genitalversinofSLI,manifested in aspecificdissociationbetweenregulara nd irregu-la rg r a m m a t i c a lmorpho logy, with relativespar ingofi rregu lar forms.Theysuggestedtha t sucha dissociation ispossiblebecausei rregulars areprocessedi n trie lexicn, vvh i leregulars are handled by a seprate gram mat ical processor. However. a mo re compre-hensivestudyof the same family byVargha-Khademet al. (1995)h as shown tha tt he


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I4c9 Introduccin to Word learningaffectedmembers of thisfamilyare equallyimpairedon both regular and irregu lar mor-phemes,aswellas on ahostofother languageandnonlanguage measures. Marchmanet al. ( 1 9 9 5 )have investigated the proposed regular/ irregula r past-tense dissociationin alargesampleofchildren withSU.They reportsigni f icantimpairmcntsinpast-tensemorphology for SLI children compared withage-matchedcontrols. However, they findno evidencewhatsoever for a dissociation between regular and i r regula r forms. 'Theerrors produced by chi ldren with SLI ar e quite s imilar to those of younger n o r m a lchildren- therea rejust moreo fthem (especially omissions).Regardless ofone'sposition on this question, we shall seelateron that the selectivevulnerabi l i ty ofgramma tical morphologyis not specitictoSLI.It h asbeen observedina numbero f other child an d a du l t populations,includingchildren with Down Syn-drome (Chapman,1995; Contardi&Vicari, 1994).Forpresent purposes. thepointisthata certaindegreeofdissociabilityhasalreadybeen observed between grammati calmorphologyandother aspectso flanguageinolder childrenandad ults with languageimpairments.Whatw ewant todetermine next iswhetheranalogous patternsofdis-sociation are observedin theperiod when grammar firstdevelops.

Lateanaearly talkersWithin alarger program lookingforpatternsofassociationanddissociation withinandacrosslinguistic and cognitivedomains. Thaland hercolleagueshave examined pat-ternso flexicaland grammatical developmentininfantsa nd preschool childrenat theextreme ends of the normal d istribution(Thal , 1991; Tha leta ., 1996). This includes"latetalkers." defined aschildrenin the bottom lOth percen tile for expressive vocabu-lary between 18and24monthsofage.in theabsenceof thesameexclusionary factorsthat are used to diagnose SU in older children. It also includes "early talkers," definedas children in the top lOth percentile for expressive vocabulary between 12 and 24months of age. For our purposes here, we are interested in the relationship betweengrammarandvocabulary intheseextremegroups.Iflatetalkersconstitutean earlyvariantofSLI. thenwemight expectto findthat grammar lags behind vocabularylevel.compared with children who reach the samevocabulary size closer to the normativeage. Alternatively, we might find some late talk ers who havemanagedto develop gram-matical abilities wellinadvanceoftheirlexical levis.Thesametwoextremesmayalsobe observedamongthe early talkers: children whose grammatical abilities are stilltiedto chronological age. despite their lexical precocity. and children who are "grammargeniuses." attaining levis of sentence complexity that are even greater than theirabilitiesin thelexical domain.

These were reasonable hypotheses, but they have not been su pported by the da ta. Instudy after study. grammatical development appears to be tiedto lexicalleveleven inchildrenat the farendsof thecontinuum,inpatterns s imilartothose displayedby thetwo extreme longitudinal cases in figure 10.6. Some further insights into this issuecome fromcase studies of children with extremely precocious language development(Tha l et al.. 1996). In one of the childreni n this study, grammar di d appear to lagb e h i n dvocabularylevel, suggesting some degreeo fdissociation. However.a deta i ledcomparison of the free-speech data and parent report data revealed an unexpectedlystrong association between vocabulary development and inf lec t ional morphology for

On the Inseparability of Grammar and trie Lexicn 749both these chil dren. even thoughone ofthemhas barely moved out of the single-wordstageThisconclusinisi l lus tratedin Table 10.2 (from Thal et al., 1996),which providesexamples of theutterances producedby MW(17monthsodwithanexpressive vocabu-lary of 596 words in the CD1)and SW (21 monthso dwithan expressivevocabularyof 62 7 words on the CDI). With an MLUof 2.1 3, MW isr i gh t whcre we wouldexpecther to be in grammar, given he r vocabularysize (equivalent to performance by anaverage28-30-month-oldchild in both domains). By contrast, SW has just begun tocombine words (MLU1.12) despite her huge vocabulary. In fact. her grammaticalabilities ar e quite average for a 21-month-old child. At first glance it appears thatSW representsastriking dissociation between grammarandvocabulary.However, theexamples n Table 10.2 reveal a very curious phenomenon:production of wordswith contrasting inflections (e.g., 'falling. . .fell") insingle-wordutterances.Thisis avery od dphenomenon fo rchildren acquiringEnglish,although it has been observedin chi ldren acquiring a highly inflected language such as Turkish (Slobin. 1985).Applying the criteria for morphological product ivi ty developed by Brown ( 1 9 7 3 ) .Thal et al. discovered that both children have about as much controlover Englishmorphology as wewould expect to find in a 2.5-year-old child.In fact,SW wasactu-allymore advancedthanMW ingrammatical morphology(i.e.,pro ductive control overmore morphem es according to Brown's rul es), although both children are well withintherangethatwewould expectforchildrenwithmorethan500words (Marchman&Bates. 1994).If the difference between MW and SW does not represen a clear dissociationbetween grammar and vocabulary, how can we explain their striking differences inutterancelength?Thalet al. notethatSWproduced carefully articulated single words.By contrast,MW wasobservedto uselonger utterances that often appeared formula icinnature. Herparents indicatedthat MWcould rememberandproduceanumberofsongsand idiomatic expressions (e.g.,"Noway,Jos,"or ''Youlittle monkey ").In fact,to thesurpriseandamusementof hermotherand theexperimenten MWproduced anovel juxtaposition of two established formulaeduring one of theexperimental ses-sions: "Noway,youmonkey " Thalet al. tentativelyconclude that these twochildrendifferprimarily in the sizeof the unit thatthey areableto store in aud itory memory,and/or the sizeof the unit that theyare able toretrieveand reformulate in speechproduction (see also Peters, 1983). As we shall seeshortly, this kindofprocessingaccount will prove useful n explainingth e appa rent dissociations observed insomeclinicalpopulations.

Early focal lesioneA different perspectiva on the relationship betweenearly grammar and thelexicncomes from studies of infantsand children with early focal brain lesionsto the left orr i gh themisphere. usual ly due topre- orperinatal stroke(Bates et al . . 1997: Reillye tal.. 1998). When cases with intractab le seizures orothermed ica l complicat ions ar eexcluded.most studies of thispopula t i on reportl a ngua geabil i t ies tha t are well with inthe normal range. regardless of lesin side. si/e, or site (Bates et al.. 1999: Kisele&A r a m , 1995; Fe ldmane tal.. 1992 :Va rgha -Kha de me lal.. 1994). As agroup.ch ildren


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Table 10 2 Examples of language production by two very early talkers (from Thal. Bates,Zappia,&Oroz, 1996)MW:Age: 1 7monthsodVocabulary 59 6 wordsVocabulary age: 30 monthsMLU: 2 .13MLUage: 28 monthsWhere cup went?Where chair went?Teddybear went?Babydoing?Wannawalk ebaby.Wannaput it on.Wanna gorideit.Want mo mge toff.Daddy take her. (referring to self)Helpwith the apple.Can'tget the teddy bear.Teddybearthe bath.Too much carrots on thedish.Moveitaround.Cleane bottom.Put ne sof.Put ineye.Momrnywearhat.Mommysmelli t.Mommy read thebook.Mommy sitdown.Find Becky.See Becky in the morning.Beckyisnice.SawBeckyandgoats.

SW:Age: 21 monthsodVocabulary: 62 7 wordsVocabularyage: >30 monthsMU 1.1 9ML t Jage: 20monthsPretty.Cute.Big.Round.Dry.Hungry.Wet.Different.Enough.Else.More.Minute.Brushing.Hiding.Babycrying.Hold.Holdit.Dropped t.Bringi t.Falling.Fell.Talk.Talking.VVash'em.Shirton.Teddyu p.Mommy shoe.

On the In&eparability of Grammar and the Lexicn 151with unilateral brain damage tend to performbelownormalcontrols.bul do notqualifyfor a diagnosis of aphasia. This conclusin holds even for chiklren whose injuriesinvolvethe classical language xones,and forsome childrenwhohavehad the entire lef themisphere removed. Jn fact, when children withearly lesin onset are studied after5-7 years of age, curren t evidence suggests thatthereare nosignificant differenccs atall between children with left- vs. right-hemisphere injury.Inviewof allthis evidence forplasticity, whatc an children withfocal brain injurytellus ab out the re lationship between gramm ar and the lexicn? The stereotypicalvicwof aphasia inadu lts might lead one to expect that these childrenwould provideevi-denceforadissociation between gramm arand thelexicn- atleastin theearly stages,when theyar etryingto getgrammarof ftheground. Instead. children with early braininjuriesshowatight relationship betweendficitsobservedingrammarand the lexicnacrossth eyearsin whichthese skills develop (Bateset al., 1997; Vicarietal., 2000).Before 5-7 yearsof age. braindamagedoes exactaveryheavycost: regardlessofsideor siteofinjury, infants with early unilateralinjuries are often 10-20 mon ths behindthe normf ortheirage.Furthermore,we can findspecific effects of lesin side and siteduringtheyearsinwhichlanguageis firstacquired- butsurprisingly,theseeffects bearlittleresemblance to the lesion-symptom correlations observed in adu lts with aphasia.For example, initial delays in "cracking the code" (word comprehension and gesture

from 10-20months) are actually greaterin infants with damage to the right hemi-sphere, exactly the opposite of what is typically seen in brain-injured adults. Childrenwith damage involving the frontal lobes are often especially delayed in word andgrammarproduction - but it doesn'tseemtomatterwhetherthe frontal lobe injuryoccurs on the left or right side So far,thereisonlyo neclueto theleft-hemispherespe-cialization for language that usually emerges n uninjured adults: between 1 and 5yearsof age(which is afairlylongtime), delaysnword production aregreatestinchil-dren whose lesions include the temporallobe (a sensoryrea)in the lefthemisphere. Itma y seem strange that asensoryrea isassociated with p roduction delays,bu tBateset al.(1999)point out apossiblereasonf orthiscorrelation: When children arelearn-ing to talkfor the firsttime, theyhave tocarryout a much more detailed perceptualanalysis of the speech signal ("hearingfor productio n") than they need to figure outwhatthosewordsmeanin the first place ("hearing for understanding"). By 5-7 yearsofa ge(including longitudinalsamples),all oftheseeffects seem todisappear.Althoughbrain-injured children are stillslightly behind normal controls, there are no left-rightdifferences (atleast not inmostwell-controlledstudies), and the children have almostall movedinto the normal range.One finalconclusin ismost importantf orpresent purposes:If children with earlyfocalbrain damagearedelayedinvocabulary, theyaredelayedingrammar- andviceversa. Thereseemsto be noevidence inthispopulationfor aspecific lesin tha t selec-tively affects grammar (leaving vocabulary intact) or selectively affects vocabulary(leavinggrammarintact). To Ilstratethis last point. figure10.9 shows the relation-ship between grammar and vocabulary for 19 individual children in the Bates et al.(1997) study. compared with th e means for normal controls at different vocabularylevis between 19 and 31 months of age from the MacAr thur COI norming study(Fensonet al., 1994) .W ehave plottedgrammatic al complexityagainst vo cabulary si/enthisfigure in aform thatfaciltalescomparisonbetween the focal lesindataand the


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752 Introduccin to Word Learning

ESO

A +Left temporaldamageA Leftdamage with temporalsparingo Rightdamage

OntheInseparability of Grammar and the Lexicn 53

50 100 150 200 250 300 350 400 450 500 550 600 650 700Vocabulary size

Figure 10 9 Grammar as a function of vocabulary sizei n children with focal brain in jury(Unes= lOth. 50th& 90th percentilefo r normis).

otherpopulationsconsidereds ofar.Sepratesymbols areprovidedt o distinguish caseswith left-hemisphere injuriesinvolving thetemporallobe,left-hemisphereinjuriesthatsparethe temporal lobe,and right-hemisphere damage. Thethreeunes in figure 10.9represen the 1 Oth,50th.and90thpercentilesforgrammaras afunction of vocabu-lary sizein theFensonet al. normativesample.Itshould beclearfromthisfigurethatchildren with focal brain injury display the normal nonlinear relationship betweengrammar and vocabulary, even though some of them are markedly delayed on both(clustered in overlapping symbols in the bottom left quadrant). Of course there issome variance around this function, but the variance is no greater than we observewith normal children. Eighteen out of 19 focal-lesion cases fall with in the 10-90windowfo r normal children. and one falls outside;w e would expect between 1 and 4cases to fall outside that window f we were drawing children randomly from thenormalpopulation. Inshort,thereis noevidencef oradissociationbetween vocabularyandgrammarinthisphaseof development, even inchildrenwho havesuffered pre-orperinatal injuriesto the classical language zones within the lefthemisphere.

Williams Syndrome and Down SyndromeWilliamsSyndrome (WMS) and Down Syndrome(DNS) areg enetically based formsofmental retardation(Bellugie tal.. ]994: Contardi& Vicari, \994; Giannott i &Vicari.1994: Mervis et al.. 1999: Miller. 1992). In both groups. mean [Q sgenerally hoverbetween 40 and 60. al t houg h a broader range of JQ scores can be observed at every

stagefrom infancy throug h adulthood. People with WMS and DN S tend to end up inthe samespecialclassroomsand residential centers; some adultsareabletohold downsimpleJobs, bu t they are rarely ablet olive independently.Despitethesesimilaritiesi nglobal IQa nd lifeexperience, recent studieshave revealedsharpcontrasts between thetwo groups. For our purposes here, we are particularly interested in the claim thatWM S and DNSrepresen a doubledissociation between languageand nonlinguisticcognition. and betweenlexical and gramma tical aspectsoflan guage processing.Children with DNS are markedly delayed in the acquisition of language. Moreimportantly. their languageabilitiesa t virtuallyevery stage(including theadultsteadyState)fallbelowthe levis that we would expect based upon their mental age (Chapman,1995; Miller. 1992). Furthermore, children and adults with DN Sappear to beespecially impaired in the production of bound and free grammatical morphemes.constituting a form of congenital agrammatism that is even more severe than theselective delays in grammatical morphology reported for children with SpecificLanguage Impairment. The function word omissions and structural simplificationsproduced by older children with DNS are especially salient in a richly inflectedlanguage like Italian (Contardi& Vicari, 1994), resultingin profiles that are quali-tatively similar to much younger normal children. although rates of omission areactually higher in DNS than controls when mean length of ut terance iscontrolled

(Fabbrettie t al., 1997).Bycon trast. older children and adults with WM Sdisplayleviso flinguisticknowl-edgean d language us ethatar esurprisingly good when theyar e compared withthelowlevis of performance shown bychildren withDNS at the same mental age (Bellugietal.,1994; Karmiloff-Smithetal., 1995; Mervisetal.,1999).This doesnotmeanthatindividuis with WMS are"language savants." Those studies that have used normalcontrols haveshown that the linguistic performance in WMSfalls invariably belowchronological age - which is, of course, no t surprising fo r subjects with an IQscorearound 50 . When children withW MS arecompared with younger normis matchedfor mental age,the picture ismixed. On most measures, performancesclosely tied tomental age (Capirci et al., 1996: G iannotti &Vicari. 1994: Volterra et al., 1996). Per-formance above mental age isobserved in children withWMS in two kindsof tasks:language tasks that draw heavily on auditory short-term memory (Wang&Bellugi,1994),and/or language tasks that elicitaffectively charged andcolorful speech (Reillye ta l . .1991).The peculiar patterns of sparing and impairment that are observed within thelanguagedomainin W MS arecomplemented byequallyinterestingpatternsofsparingand impairment outside of language. For example, people with WMS and DNSdiffermarkedly inbasic measuresof information processing. WM S en dto beextremely sen-sitivetosound (i.e., hyperacusis). andtheyperformsignificantlybetter than IQ-matchedindividuiswithDNS on testsofauditory short-term memory(Contardi &Vicari,1994;Vicarie t al., 1996: Wang&Bellugi.1994).DNS isoftenassociated withmildt o mod-ratedficits in hearing, but DNSchildren showsignificantly better performance thanage-matched W MS ongestural tasks. and DNSadults perform significantly better thanWMS adults on measuresof visual short-termmemory.Thesedifferences inprocessingmodalitym aybe relevant to the contrastinggrammaticalprofilesobservedin WMS andDNS (seebelow).


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154 Introducton to Word LearningBased on findingslike these, th e initia)viewof W MS aslanguagesavantshas girenwayto an interest n thissyndromefor the insightt hat this syndrome offers into Ian-guage deve/opment under different condit ionsof information processing (especiallyauditory processing), affect and cognition (seeKarmioff-Smith, this volume).One ofth emost interesting questions revolves around the relationshipbetweengrammara ndthe lexicn in peoplewithW MS. Earlierpapersdescribing angua ge in WM S suggestedtha t grammar may be"spared"while semantics and pragm atics aredeviant or "odd"(Bellug et al., 1994:Reiiiye tal.. 1991). Pinker( 1 9 9 1 ) ha s madet he further sugges-

tion that WMS may bepart icularly adept in the use ofregularmorphemes, resultingin overgeneralization errors on irregular forras (e.g.. "goed" instead of "went").Iowever, more recent evidence suggests that grammar andlexical semanticsare bothabnormal in the WMSpopulat ion.Rubba an d Klma (1991)haveshown that English-speaking WMS produce peculiar substitutionso fprepositional forms. Karmiloff-Smithan d colleagues have provided evidence suggesting thatFrench-speaking W MSfind itdifficult to generalize regular gender morphology tonovel words- even though theyare very good at repeating the same noveliteras.C omparative studies of WM S and DNSin Italian suggest that both groups aremarkedly impaired in theproductiono f gram-matica l morphemes, includ ing both regular and irregular forms. However, the twogroups differ markedly in the kinds of errors they produce. As noted above, Italian speakers withD NStend to err by omisson and simplification, yieldngprofiles similar ftothosethatareobservedinItalianBroca'saphasics, Italians withSLI,andvery young talian-speakingnormis. By contrast, Italian speakers with WMS have been shown to Iproduce arangeof morphological substitutions thatarerarelyobservedinnormis atany age, bearing a distantresemblance to the substi tut ionerrors observed inItal ianWernicke's aphasics(Batesetal., 1991).

Inviewof themanycontrasts observedin olderchildrenand adolescents withWMSsyndromevs. Down Syndrome, it isinteresting to askjusthow early the two groupsseprateintheirprofiles of Iangua gedevelopment . Is the Ianguage advantage in WMS(or the Ianguage disadvantage in DNS) present from the very beginning, or does itemerge onlyafter somecritica cognitiveo r linguisticmilestoneisreached? This ques-tion was addressed by SingerHarris et al. (1997), who used the MacArthurC D toobtainearlyIanguage data from alargesample of children with WMS or DNS betweenone and sixyears of age. In the period of development covered by the infant scale(equivalentto normal children between8 and16months),WMS and DNSwere equallyand severely delayedinboth word comprehension and word production.The predictedseparation between WMS and D NS did not emerge until the period ofdevelopmentcovered by the toddler scale (equivalent to normal children between 16 and 30months). Bothgroupswere stilldelayed by approximately twoyearsat this point, withno significantdifference in overall vocabulary size. However, Singer et al.found strik-ing differences in the emergence of grammar. Interestingly, this difference relects aDN Sdisadvantage rather than a WM S advantage.

To faciltatecomparison acrossgroups.we have plotted the data forindividualWM Sand DNSfromSinger H arris et al. in figure10.10,in the same formatadoptedthrough-out this chapter. W ithin WMS. gramm atical development appears to be paced by vo-cabulary size, in the normalfashion. In fact. when these childrena re compared withlexically matched normal controls from th e CDJ sample, th e re la t ionsh ipbetween

On the Inseparabilty of Grsmmar and the Lexicn 55o Williams Syndrome

Down Syndrome

50 100 150 200 250 300 350 400 450 500 550 600 650 700Vocabulary sizeFigure10 10 G r a m m a ras afunct ion ofvocabulary sizei n children with Williamsvs.DownSyndrome (lines= lOth. 50th&90thpercentile for normis).

grammar an d vocabularysize isidentical .following the same nonlinear acceleratingfunction described abovef ornormis and forchildren withfocalbraininjury. Inshort,there is no evidence for a dissociation between gram matic al and lexicaldevelopment inWM S- atleastnot inthis early phaseofgram matical development.By contrast, the DNS sample provideso ur best evidence to date for a significantdissociation between grammar and the lexicn. In part icular, DN Schildren scoredsignificantly below the grammatical levis displayedb ynorma l childrenand by WMSmatched or vocabulary size(Figure 10.10).However, the term "dissociation" must beused with caution here.C orrelat ional analyses show that grammar and vocabularyar e tightly related in both children with WMS and children with DN S(correlatingaround +.70). Thereis arealdifference between these groups,but itliesin theamountof vocabulary that children in each group seem toneed in order to get grammaro ffthe ground: WM S need the sameamount required by normal children of the same mentalage,while DNS requiremorethanthenormalamountofvocabulary inorderfor grammartoemerge.

As wenoted earlier. therei s adouble dissociation nthesetw ogroups between audi-tory short-term memory (signiflcantly better inWMS) an d visual short-term memory(significantly betterinDNS).I tappears thatD NSsuffer from a select ive impairmentinone orm ore aspectso f auditory processing,a dficit that issuperimposedu pontheirmore generalcognitive delay. Unde r thesecircumstances. it isperhaps no t surprisingthe DNS are selectively impaired in the ability to detect. store, and/o r retrieve thoseaspects of their l inguist ic i n p u t t h a t ar e lovvest in what I.eonurd (1998) refers to as


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56 Introduction to Word Learning"phonologicalsubstance," orsalience. Thisargumenti ssimilarto onethatTallal andhercolleagues have usedt oexplaint heselective grammaticaldficitsdisplayedb yolderchildrenwith SU (Tallale t al., 1985) . W ewill return to thisissuelatero n,with refer-encet oselective impairme ntsofgrammar in brain-injured adul ts .

Explaining the LinkWhyis the relationship between grammar and the lexicn so strong in this period ofdevelopment?The same basic nonlinear relationship appears in longit udinal and cross-sectionaldata, in at leastt wo dramatically dfferent languages (see Caselli et al., thisvolume),indifferentdomains of grammar. in children who are developing on a normalschedule and in child ren who are developing at an aberrant rate. We do find a viola-tionof this relationship in children withDownSyndrome, but the deviation seems toinvolvenot a dissociation between gram mar and the lexicn, but a pathologica ldiffer-ence in the amount of vocabulary required in order to learngrammar. There is no apriorireason why this had to be the case. Por example, many adults who try to acq uirea second language in the classroom find themselves in a situation in which theirstockof grammatical rules outstrips their limited vocabulary.The dependence of earlygrammar on vocabulary size is so strong and the nonlinear shapeof this funct ion issoregular th at it approaches the statu s of a psychological law. akin to the reliable psy-chophysical functions that have been observed in perception (e.g.. Weber's Law,Fechner's Law).But explanationbylegislatura is not very satisfactory,and it isparti-cularly unsatisfactory if better explanations are available. We can offer at least fivereasonswhygrammarand vocabulary trackeachother socloselyinthis stageof lan-guage development. None of them are mutually exclusive.

1 Perceptual bootstrapping Nusbaumand Henly(1992) have proposed thatefficientword perception requires acertain amountof top-down processing, per-mitting the listener to weed outinappropriate candidates froma large pool oftemsthatoverlap (at least partially) with the blurred word tokens that so oftenoccurinfluent speech.To the extent thatthisistrue.it isprobably evenmoretrue for the perception of grammatical function words and bound inflections.For a variety of reasons. these units are particularly hard to perceive (Herrn &Bates.1997;Hurlburt&Goodman. 1992:Leonard. 1998).Theytendtobeshortand low instresseveninspeech thatisproducedslowlyanddeliberately. Ininfor-malandrapid speech, speakers haveatendency toexploitthefrequencyandpre-dictability of funct ionwordsandbound morphemesbygiving them short shrift.deformingtheir phonetic structure and blurring the boundaries between thesemorphemesand thewordsthatsurround them.Infact,when grammatical func -tion words are clipped out ofconnectedspeech and presented in isolation. adultnative speakers canrecogni/ethem no morethan40-50%of the time (Herrn& Bates. 1997). This is true of speech directed to children as well as speechdirectedt oadults( G o o d m a n&N u s b a u m .1994).U n d e rthese circumstances.w eshouldnot besurprised thatyoungchildrenareunableto acquire grammatical

On the Inseparability ofGrammarand trie Lexicn 157forms untilthey have acriticalmassofcontenwords. providing enough top-down structure topermit perceptiona nd l ea rn ing ofthose "l i t t lc sounds" t h a toccur to the right or left of "realwords."

2 Logicalbootstrapping Studiesinseveraldifferent l anguageshave shown thatverbsand adjectivesare acquiredlater thannouns(see Casellielal.,thisvolume).Except for a fewterms like"up"a nd "no" that ca nstand alone,funct ionwordstend to appear later still, well after the firstverbsa nd adjectives appear. Fur-thermore, many relativelyearly prepositions(e.g.,"up") may not beused in thesame way by childre n as by adults. Adu lts use them tospecifya relation betweenobjects or a location. Children on the other hand use them to refer to events(Tomasello &Merriman, 1995) insteado fusing thema s"grammaticalglue."Ithas been suggested that this progression fromames to predication to grammaris logically necessary, based on a simple assumption: Children cannot under-stand relational terms unt il they understand thethings that these words relate.One can arge about the extent to which this assumptionholdsforindividualstructures, but it may provide a partial expianation for the dependence ofgrammar on lexical growth.

3 Syntacticbootstrapping Theperceptualandlogical bootstrapping accountsboth presuppose that the causal l ink runs from lexical growth to grammar.However, studies from severaldi fferent l aboratories have shown that childrenbetween 1 and 3yearsof age are able toexploitsentential informationtolearnabout the meaning of a novel word (Goodman etal.,1998; Naigles et al.. 1993;Tomasello, 1992).Naigles et al. (1993 ) referto this process as "syntactic boot-strapping," althought has been shown that children can usemany differentaspects of a sentence frame for this purpose, including sentence-level semantics.morphological cues, word order, and prosody. It is therefore possible that theaccelerating function in Figures10.2-10.10is due in part to the effect of thechild'semerginggrammaron lexicalgrowth.

4 Nonlinear dynamicsof learning in a neural network Theabovethreeaccounts allsupport a linkbetween lexicaland grammatical development,butitis not obvious from these accounts why the funct ion ought totakethe non-linear formthatappearssoreliably acrosspopulationsand agelevis.Wenotedearlierthatthe nonlinear funct ionsgoverning the relation between verb vocabu-lary and theemergence ofregular and irregular past-tense marking appearinasimilarform inEnglish-speaking childrenand inne ural network simulationsof past-tense learning (Elman,this volume; Marchman & Bates 1994; Plun kett&Marchman. 1993). Thisi sonly on e exampleof amore general point:Multi-layered neural networks produce an a r ray of nonlinear growth funct ions,reflecting th enonlinear dynamicsoflearningan d changei nthese systems.Th ekinds of critical-mass effects that we have proposed to underliet he relationbetween lexical and grammatical growth may be a special case of this moregeneral approach lo the nonlinear dynamicsof learn ing (Th elen & Smith.1994).

5 Lexicallybasedgrammar Finally.as wenoted at the out s e to f thispaper. th ehistorica l trend inmodernl inguist ics ha s been to place in Ihe lexicnmorea nd


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15& Introduction to Word learningmore of the work tha t was previously carried out in a seprate gram mat ical com-ponent. Th e powerful relat ion between grammaticalan d lexicaldevelopmentthat wehave observedherei spreciselywhatw cwould expect ifgrammar is aninherentpart of thelexicn.

Points 1-4 all pertain to learning. Point 5 is a stronger claim, extending to therelationship between grammar and the lexicn in the adul t steady statc. The datathat we have reviewed so far ma y be relevan only to the early stages of languagedevelopment, th e period in which th e fundamental propert ies of language-specificmorphosyntax are laiddown.Itis entirely possible that a modula r dis tinction betweengramm ar and the lexicn mayemerge at a latter point in development. in accordancewith the processeso f "modularizat ion"described byKarmiloff-Smith (1992):s ee alsoBates et al., 1988). This question is best addressed by looking at the literature onlanguage disorders in older children and adults. where strong claims about themodularity of grammar and the lexicn have been made.Our review of this literaturesuggests that the lexicalist approach stands up to the evidence for older childrenand adults as well. For every clinical group for whom grammatical dficits havebeen reported. lexical dficits have also been demonstrated. In fact, a dficit in wordfinding (called "anomia") is the one symptom that is present in every form of adultaphasia (Goodglass, 1993). Conversely. in every clinical group fo r whom lexical

dficits are reported, some kind of grammatical problem is observed as well. A par-ticularly interesting observation about these links is the fact that grammar and thelexicn tend to break down in the same w ay within individual patients. Non-fluentBroca's aphasics tend to err by omission; they leave out grammatical inflectionsand function words. but they also tend to leave out conten words (especially verbs).This omission profile is also seen (usually in a milder form) in children with DownSyndrome and children with Specific Language Impairment. Fluent Wernicke'saphasics tend to err by substitution, putting in the wrong conten word (or a blendof words). In richly inflected languages, the sametendency (cal led paragrammatism)is observed for inflections and function words. This "substitution profile" is alsoobserved in children with Williams Syndrome, if they are acquiring a languagewith enough morphology for such substitutions to surface (Volterra et al., 1996).Finally. patients with Alzheimer's disease and patients with milder forms of aphasiararely make frank grammatical errors of any kind (omission or substitution).However, they tend to avoid production of complex syntactic structures (e.g.. thepassive. Bates et al., 1995b), a grammatical symptom that mirrors their problemsin lexical production (i.e., an overreliance on pronouns and other "light forms"). Amildversino fthis"avoidanceprofile"i salsoseeni nnormal aging.Inshort, grammarand the lexicn continu to travel together in adulthood. an d they break down insimilar ways.

Grammar and the lexicn develop together in infancy, and they break down togetherin b rain-injured adults . Ino ur view, th emost parsimoniousexplanation forthese factswould be a mental /neural architecture in which grammar and the lexicn are repre-sented together,andhandledby the same mechanismsforlearningandprocessing- inshort , a lexicalist viewof the sort that ha s gained considerable acceptance inmodernlinguistics.

On the InseparaWity of Grammarand the LexicnNotes

159

1 "Observation of early stagesoflanguageacquisilionmay bequite misieadingin thisregard.It is possible tha t at an earlystage mere is use of languagelike expressions. but outside theframework imposed.a t alaterstageofintellectual maturation,by thefaculty of language-much as a dog can be trained to respond to certain commands, though we would notconclude. from this. that it is using language." (Noam Chomsky, Reflections on language(p.53 ) . NewYork,PantheonBooks, 1975).2 Wealso looked atmanyothermetrics of grammatical development,including propositionalcomplexity and morphological productivity.Aftera llthatwork weweresurprised to findthat .at least in this period of development, MLU is so highly correlated with other, moresophisticatedmeasures, thattherewas nopointin using anyotherestmate ofg rammarincorrelational analyseswith othervariables; for a discussion of thispoint.se e Bates et al..1988.

ReferencesBates.E.,Bretherton,I.. &Snyder.L.(1988).Fromfirst wordsto grammar:Individualdifferences and

dissociablemechanisms.New York:CambridgeUniversityPress.Bates.E..Dale.P., &Thal, D.(1995a).Individualdifferences andtheir implicationsf ortheoriesof languagedevelopment.In P.Fletcher& B.MacWhinney (Eds.), Handbook of child anguage(pp.96-151). Oxford: BasilBlackwell.Bates, E.. Marchman. V. Harris, C., Wulfeck, B.. & Kritchevsky. M. (1995b). Productionofcomplex syntaxin normal ageing and Alzheimer's Disease.Languagea ndCognitive Processes,11 ( 5 ) . 4 8 7 - 5 3 9 .Bates.E..Thal.D..Trauner,D..Fenson.J.,Aram.D..Bisele.J.. & Nass, R.(1997).Fromflrstwordsto g rammarin childrenwith focal braininjury. In D.Thal& ].Reilly (Eds.). Special issue onOriginsof CommunicationDisorders.DevelopmentalNeuropsychology. 13 (3). 275-343.Bates. E.. Vicari. S.. & Trauner, D. (1999). Neural mediation of language development:Perspectives from lesinstudies of infants and children. In H.Tager-Flusberg (Ed.), Neurode-velopmentaldisorders (pp.533-581).Cambridge,M A:MITPress.Bates. E.. Wulfeck. B., &MacWhinney. B. (1991). Crosslinguistic research in aphasia: Anoverview. Braina ndLanguage.4 1. 123-148.Bellugi. U.,W ang. P.P.. &Jernigan. T.L. (1994 ).Williams Syndrome:A n unusual neuropsycho-logical protile. In S. Broman&J. Grafman (Eds.), Atypical cogntive dficits in developmentaldisorders: Implicationsfor brainfunction. Hillsdale.NJ:Erlbaum.Bickerton.D .(1984).The languagebioprogramhypothesis. Th eBehavioraland BrainSciences. 7.173-187.Bishop. D.V.M. (1997). Uivammon understanding: Development and disorders of comprehension inchildren. Hove,U K:PsychologyPress.Bloom.L.(1991). Languagedevelopmentfrom twotothree.NewYork:CambridgeUniversityPress.Bresnan,J.(2001).Lexical fimctionasyntax.Malden.MA: Blackwell.Brown,R. (1973). A flrst anguage: Theearly stages. Cambridge.M A:Harvard UniversityPress.Capirci. O..Sabbadini.L .,& Volterra. V.(1996) .Language developmentin WilliamsSyndrome:Acasestudy. Cotmitin' Ncwopsi/r/io/oiji/. J3 7) , 1017-1039.

Caselli.M .C . ,Casadlo. P, &Bates.E . (1999). Acomparisonof the transition from tirst words togrammari nEnglish and Italian.Journal of (.'luid Limauaie.26, 69-111.


15/16

16O Introduccin to Word LearningChapman. R.S. (1995). Language developmenl n children and adolescents with Down

Syndrome. In Paul Fletcher & Brian MacWhinney (Eds.). The handbook of child language(pp. 664-689).Oxford: Basil Blackwell.Chomsky.N. (1965).Aspects of thetheorij ofsyntax.Cambridge,MA:M ITPress.Chomsky.N. (1975. Reflections anlanguage.New York.PantheonBooks . 1975).Chomsky, N. (1981). Lecturesongovernmenl and binding.N ewYork: Foris.Chomsky.N .(1995) . The minimalist program.Cambridge.MA: MIT Press.

Contardi,A.. Vicari,S .(Eds.). (1994).L epersone Down: Aspetti neuropsicologid, educativiesociali.Milano: FrancoAngeli.Dale.RS .(1991) .Th evalidityof aparent report measure of vocabulary and syntax at 24 months.Journal of Speech and Hearing Sdences. 34. 565-571.Dale,RS..Bates.E., Reznick.S..&Morisset. C. (1989) .Th e validityof aparentreport instrumentof childlanguage a t 20 m onths . Journal of ChildLanguage, 16,239-249.Eisele. }., & Aram. D. (1995). Lexical and grammatical development in children withearly hemisphere damage: A cross-sectional view from birth to adolescence. In P. Fletcher& B. MacWhinney (Eds.), The handbook of child language (pp. 664-689). Oxford: BasilBlackwell.

Elman,J ..Bates,E. ,Johnson. M.. Karmiloff-Smith, A..Parisi. D..&Plunkett .K.(1996) . Rethnk-ing innateness: A connectionist perspectiveon development. Cambridge.MA: MIT Press/BradfordBooks.

Fabbretti, D., Pzzuto. E., Vicari, S., &Volterra .V (1997). Astory description task in childrenwith Down syndrome: lexical and morphosyntactic abilties.ournal ofIntelectual DisabilityResearch.41 (2),165-179.Feldman.H., Holland. A.,Kemp.S.,SJanosky, J. (1992). Language development after unilateralbrain injury.BrainandLanguage.42, 89-102.

Fenson.L.Dale, P, Reznick,J.,Bates,E .,Thal,D..& Pethick. S. (1994 ). V ariability in early com-muncative development. Monographs of the Sodety for Research in Child Development,SerialNo. 242. Vol. 59. No. 5.Fillmore, C.J., Kay, R, & O'Connor, C. (1988). Regularity and idiomaticity in grammaticalconstructions: The case of LetAlone.Language,64. 501-538.Fodor, J.A. (1983). The modularity of mina: An essay onfaculty psychology. Cambridge,MA: MITPress.Garret t ,M. (1992). Disordersof lexical selection. Cognition.42, 143-180.Giannott i ,A. ,&Vicari,S. (Eds.).(1994) .Ubambinocon sndrome diWilliams.Miln: FrancoAngeli.Goldberg, A.E. (1995). Constructions:A construction grammar approach to argument structure.Chicago: Universityof ChicagoPress.

Goodglass. H.(1993) . Understanding aphasia.SanDiego: AcademicPress.Goodman,J.C.(1995). Theshapeofchange:Longitudinal evidence about language development.Sodety forResearchinChild Development Abstrais. 10. 111.Goodman.J.C..McDonough,L. ,&Brown.N.B. (1998) .The role of semanti c context and memoryin the acquisition of novelnouns.ChildDevelopment. 69 (5 ) ,1330-1344.Goodma n ,J.C..&Nus ba um, H.C. (Eds.). (1994). The development of speech perception: Tnmsitionsfrom speech sounds tospoken words.Cambridge. MA: MITPress.Gopnik.M .(1990).Feature-bl indgrammar an d dysphasia. Nature. 34 4 (6268) , 715.Herrn, D..& Bates, E.(1997) . Sentential and acoustic factors n the recognition of open- andclosed-class words. Journal of Memory andLanguage,37 (2 ) ,217-239.Hurlburt , M.S. , & Goodman. J .C. (1992). The development of lexical elTecis on children'spilneme identilications. In ].].Ohala , T.M. Nearey.B.L. Derwing. M .M.Hodge, & t.E. Wiebe(Eds.) , ICSLP 92 Proceedings: 1992 International Conference on Spoken Language Prncessing(pp. 337-340).Banff.Alb erta . Canad:University ofA lbe r t a .

r On the Inseparability of Grammara nd the Lexicn ]Q \Jahn-Samilo. J. (1995) . L a ngua gecomprehension and production in children from 8 to 30months of age: Acomparison of parent report and laboratory measures from a longi tudinalstudy.Sodetyf or Researchi nChild Development Abstracts, 10, 112.Jakobson.R .( 1968) . Child language aphasia andphonological universals.Paris: Mouton.Karmiloff-Smilh, A. ( 1 9 9 2 ) . Beyond modularity: A developmenlal perspective on cognitive science.Cambridge. MA: MIT Press.Karmiloff-Smith, A. .Klima,E.S..Bellugi. U. ,Gra n t ,J..&Baron-Cohen,S .(1995). [stherea socialmodule?Language.face processing,a nd theory of mind insubjectswith Will iams Syndrome.Journal of CognitiveNeiirosdence, 7 ( 2 ) . 196-208.Langacker.R .(1987) . Foundations of cognitive grammar.Stanford: Stanford Universily Press.Leonard. L.B. (1998) . Children with spedfic languageimpainnent.BostonMA: MTPress.MacDonald. M.C.. Pearlmutter. N.J..& Seidenberg. M.S. (1994). Lexical nature of synlacticambiguity resolution. Psychological Review, 101 (4),676-703.MacWhinney. B. (1 9 9 3 ) . Connections and symbols:Closing the gap. Cognition.49 (3), 291-296.

MacWhinney. B., &Bates.E. (Eds.).(1989). The crosslinguistic study of sentenceprocessing.NewYork:Cambridge University Press.Marchman. V., &Bates.E .(1994) . Continuityin lexicala nd morphological development:Atestof the criticalmasshypothesis. Journal of Child Language,2 1 (2 ) ,339-366.M a rc hma n . V,Wulfeck, B.,& Weismer, S.E. (1995) . Productiveuse of Englishpast-tense morpho-

ogy n children with SLI andnonnal language(Tech. Rep. No. CND-9514). La Jolla: Universityof California. Sa n Diego. Center for Research inLanguage. Project inCognitive and NeuralDevelopment.Marcus .G .,Pinker,S ..U l lma n .M.,Hollander.M. ,Rosen. T.J.,& X u .E (1992). Overregularizationin language acquisition. Monographs of theSodety forResearchinChildDevelopment, 57.Mervis, C. Morris. C., Bertrand, J.. & Robinson. B. (1999). Williams syndrome: findings froman integrated program of research. In H. Tager-Flusberg (Ed.), Neurodevelopmental disorders(pp.65-110).Cambridge.M A: MITPress.Miller, J. (1992). The development of speech and language in children with Down Syndrome.In E.McCoyand I. Lott(Eds.),Clinicalcarefor persons with Down Syndrome (pp.121-138).Ne wYork: Academic Press.Naigles, L. , Glei tman,H.,& Gleitman. L .R. (1993). Childrenacquirewordmeaningcomponentsfrom syntactic evidence. In E.Dromi (Ed.), Language andcognition:A developmental perspective(pp. 104-140). Norwood.NJ: Ablex.Nelson, K. (1973). Structure and slrategy in learning to talk. Monographs of the Sodety forResearchin Child Development.38 (1 &2 . Serial#149).Nusbaum. H.C.,&Henly,A.S. (1992). Liste ning to speech throu gh an adaptive window ofanaly-sis. In B.Schouten (Ed.).T heprocessingof speech: From the auditory periphery toword recognition.Berln:Mouton-De Gruyter.Peters. A. (1983) . The unitso f languageacquisition.Cambridge: CambridgeIJniversity Press.Pinker,S. (1991 ). Rules of language. Science.253. 530-535.Plunkett , K.. &M a rc hma n . V.(1 9 9 3 ) . From rote learning lo system building: Acquiring verbmorphologyinchildrenandconnectionis tnets.Cognition.48.21-69.Pollard. C.. & Sag, I. (1994). Head-drive phrase structure grammar. Center for the Study ofLanguage and Inform ation. Report # CSLI-88-1 32. Universityof Chicago.Reilly. J..Bales.E..&M a rc hma n .V . ( 1 9 9 8 ) .Narrat ivodiscoursein childrenwi thearlyfocalbraininjury. In M.De nn i s( l i d . ) . Special issue. Discoursein childrenw i th a noma lousbrain develop-me nl oracquiredb ra in injury. BrainandLanguage.6 ( 3 ) . 3 3 5 - 3 7 5 .Reilly. J..Kl ima.F...& Bellugi. U.( 1 9 9 1 ) .Once more with feeling: al ' f ect and l a ngua gein atypic alpopulal ions . Developmental Psychopathology. 2. 367-391 .


16/16

J62 Introduccin to Word learningRubba, ]., &Klima, E.S. (1991 ). Preposition use in a speaker with WilliamsSyndrome: Somecognitivegramm ar proposals.Center forResearchinLanguageNewsletter Val. 6.N o.1.Universityof California, San Diego.Shore, C.M. (1995) . Individua differences in language development. Thousand Oaks. CA: SagePublicalions. Inc.Singer Harris,N., Bellugi. U.. Bates. E. , Jones.W.. &Rossen.M. (1997). Contrast ingproileso flanguage development inchildren with Williams and Uown Syndromes.In 1). Thal& }.Reilly(Eds.).Specal issue on originsof Communication Disorders.Developmental Neuwpsychology,1 3 ( 3 ) . 345-370.Slobin. D. (Ed . ) . (1985-1997) . The crosslinguistic study of language acquisition (Vols. 1-4).Hillsdaie, NJ: Erlbaum.Tallal. R.Stark.R..&Mellits.D.(1985).Identification of language-impaired childrenonthebas i sof rapid perception and production skills.Brain andLanguage.2 5. 314322.Thal. D.(1991).Language andcognitioninlate-talkingtoddlers.TopicsinLanguage Disorders.11.33-42.Thal. .. Bates.E ., Goodman,J ..&Jahn-Samilo, J. (1997). Continuity of language abilities inlate- ar.d early-talking toddlers. In D.Thal & J.Reilly(Eds.),Special issueon Originsof Com-munication Disorders,Developmental Neuropsychology. 13 ( 3 ) ,239-273.Thal. D..Bates.E.,Zappia.M.]..&Oroz.M .(1996). Ties between lexicala nd grammatical devel-opment: Evidencefrom early talkers.Journal of ChdLanguage. 23 (2). 349-368.Thelen.E..&Smith.L.B.(1994).A dynamic systernsapproach to thedevelopment of cognitionand

action.Cambridge.MA: MITPress.Tomastllo. M. (1992) . First verbs: A casestudy of early grammaticaldevelopment. Cambridge.UK:Ne wYork:Cambridge University Press.Tomasello.M..&Merriman,W. (Eds.)(1995).Beyond amesfor things:Yoitng children'sacquisitionof verbs.Hillsdaie. NJ:LawrenceErlbaum.Vargha-Khadem. E, Isaacs. E., &Muter, V.(1994). A review of cognitive outcome after unilat-erallesionssustainedduringchildhood.Journal of ChildNeurology, 9 (SuppL),2S67-2S73.Vargha-Khadem, E,Watkins, K..Alcock. K.. Fletcher. E, &Passingham. R.(1995). Praxic andnonverbal cognitivedficits in a largefamily with a genetically transmitted speech and lan-guage disorder.Proceedings of theNationalAcademy of Sciences USA,92 .930-933.Vicari,S.,Albertoni, A..Chilosi.A.. Cipriani,E.Cioni, G.. &Bates.E .(2000). Plasticity and reor-ganization during early language learning inchildren with congenital brain injury. Cortee. 36 .31-46.Vicari.S..Brizzolara, D..Carlesimo,G.A., Pezzini.G. .& Volterra. V.(1996). Memory abilities inchildren with Williamssyndrome.Cortex. 32 (3) .503-514.Volterra. V.Pezzini.G., Sabbadini.L,Capirci.O..&Vicari.S.(1996).Linguisticabilitiesin[tallanchildren with Williams syndrome. Cortex. 32(4) .663-666.Wang. E. &Bellugi.U .(1994). Evidencefrom two genetic syndromes for adissociation betweenverbal and visual-spatial short-term memory.Journal of Clnica andExperimental Neuropsy-chology. 16 .317-322.

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