AGE AND THE LIMITS OF L2A - University of Texas at Austin年龄和L2a -限制在奥斯汀的德克萨斯大学

TheEndStateinL2A:

Factors,Facts&FallaciesCognitiveScienceSeminarUniversityofTexas9October2021DavidBirdsongDept.ofFrench&Italianbirdsong@[paperhandouttoaccompanyslides][slidestobepostedonblackboard]1L2Aresearch

SampleofjournalsCognitionJMLJCNNatureNeuroscienceBBSBrain&LanguageLanguageAppliedPsycholinguisticsTICSBilingualism:LanguageandCognitionStudiesinSecondLanguageAcquisitionSecondLanguageResearch2L2Aresearch

Programs/LabsMcGillGeorgetownIllinoisMPI-NijmegenEssexCNRSParisAmsterdamGroningenHeidelberg3L2Aresearch

RecentPh.D’satUT-F&IRobertReichle(December2021) “Syntacticfocusstructureprocessing:BehavioralandelectrophysiologicalevidencefromL1andL2French〞ElenorShoemaker(May2021) “AcousticcuestospeechsegmentationinspokenFrench:nativeandnon-nativestrategies〞4Context:

the‘DeficitModel’tradition

Bley-Vroman(1989:44):Insignificant incidenceofnativelikenessinlateL2A L2A:“ineluctablefailure〞fossilizednon-nativeness =>FundamentalDifferenceHypothesis5Context:

the‘DeficitModel’tradition Johnson&Newport(1989:255):forAoA>15 “laterAOAdeterminesthatonewill notbecome native[like]ornear-native[like]ina[2nd]language〞 <=maturationally-basedCPH/L2A6Context:

the‘DeficitModel’tradition Long(1989:280):“Theabilitytoattainnative- likephonologicalabilities[inanL2]isbeyond anyonebeginninglaterthanage12,nomatterhow motivatedtheymightbeorhowmuchopportunity theymighthave.Native-likemorphologyand syntaxonlyseemtobepossibleforthose beginningbeforeage15.〞<=Maturational constraints

7Context:

the‘DeficitModel’tradition Hyltenstam&Abrahamsson(2003:575): Ifwelookat“overallL2proficiency〞wewillfind that“perfectproficiency〞and“absolutenativelike commandofanL2mayinfactneverbepossible forany[lateL2]learner〞<=Deficientlanguage- learningmechanisms

NB:B-V,J&N,Long,H&Acriterion=monolingualnative NB:Allapproachdeficitfromendstate(=ultimate attainment)perspective

8Context:

the‘DeficitModel’tradition W/r/tL2processing=>representationby latelearners Tsimpli&Dimitrakopoulou(2007:217): Uninterpretablefeatures(e.g.+/-case)“difficult toidentifyandanalyseintheinput〞<= “persistent,maturationally-basedL1effectson adultL2grammars〞=>roleofdetectionin unlearnabilityofuF;cf.Lardiere(2021)

NB:criterion=monolingualnative;S’snotalwaysatendstate

9Context:

the‘DifferencesModel’ W/r/tL2processingbylatelearners

Clahsen&Felser(2006:564):L2processing nativelikeinsomeareasofgrammar;however eveninhigh-proficientL2ers“differencespersist inthedomainofcomplexsyntax〞i.e,in“real-time computationofcomplex hierarchical representations〞 =>considerexplanations:deficientL2grammar (representationaldeficitvisàvisnative);L1 transfer;cognitiveresourcelimitations; maturationalconstraints NB:C&Fcriterion=monolingualnative;notallS’satendstate

10Context:

the‘DifferencesModel’

W/r/tL2processingbylatelearners

Cutler(2003,interalia):Insegmental, subsegmentalandsuprasegmental perception,L2erslistenthroughL1ears; seealsoPeperkamp,Sebastian-Galles, Dupoux,etc.

11Context:

Meisel(2021)

Meisel(2021:8)“ChangesintheL[anguage] M[aking]C[apacity]inthecourseofchildhood developmentmakeitimpossiblefortheL2learner toacquireacompletenativegrammatical competenceofthetargetlanguage〞

Meisel(2021:13)FDH“doesnotentailthatL2 acquisitionbecomestotallyorpartially impossible.Rather,theclaimisthatL2 knowledgeisofadifferentkind〞<=sourceof knowledgeisdifferent

12CurrentaL2Aworkunder‘DM’

Methodologically:

(Usually)studied: -L2high-proficients Understudied: -L2dominants (Often)notconsidered: -facilitating/inhibitingexternalfactors -individualinfoprocessingdifferences -reciprocalL2<->L1influence -AoAascomparisonconditionorcontrolvariable -assuranceofL2Aasymptote -incidence(#’s)ofnativelikeprocessers

=>Incompleteempiricalpictureofnature+extentofnative/L2 differences

13CurrentaL2Aworkunder‘DM’

Programmatically:

Data:

-variedbehavioral&brain-basedstudies -variedmethods&tasks Domains:

-rangeofprocessingandknowledgedomains

Focus:

-non-nativelikeprocessingatgrouplevel

Orientation:

-deterministicdifferences

Goal:

-theoryofqualitativeL1-L2differencesinknowledge/processing

=>Empiricalgapsw/r/tupperlimitsof(late)L2A

14‘UpperLimitsModel’ComplementingtheDMperspective:Programmatically&methodologicallyDistinguish:

-whatadultL2ersdo -whatadultL2ersdon’tdo

-whatadultL2erscando -whatadultL2erscan’tdoPopulations:

-L2dominants(twotypes) -L1attriters -(L2high-proficients) -incentivizedL2ers:functionalneedforL2nativelikeness -L2ersdesiringsocio-culturalintegration,L2identity15‘ULM’Programmatically:

Integrate:

-individualdifferencesw/r/tinternalfactorse.g.WMcomponents

Rationale: -claimsthatonlyfreakishaptitude=>nativelikeness[morelater] -WMcorrelateswithlevelofultimateattainmentinsometasks

Integrate:

-facilitating/inhibitingexternalconditions

Rationale: -incomparingL1AandL2Aendstate,leveltheplayingfield intermsoffacilitatingconditions[morelater]

-‘normal’adultL2Aconditions=abnormalforLAgenerally

Integrate:

-AoA/AoTascontrol,predictorvariables

Rationale: -weknowtheeffectsofageand+/-theirsources[morelater]

-toseewhatcanL2ersdoinspiteofageinfluences

16‘ULM’Programmatically:

Goals:

-Establishendstateprocessingprofiles: -L2dominants -definedbyL2vsL1relativeuse -definedpsycholinguistically(independentprocessing measures) -latevs.earlydominants -unstabledominants -EstablishupperboundsofL2ers’processing&knowledge:

-visàvisnatives -visàvisearlybilinguals/earlyL2ers -intheirownright(v.comparativefallacy) -keepinginmindL2<->L1influence(L1ofamonolingual≠L1ofa bilingual) -IntegrateaboveintotheoryofL2knowledge&processing atthelimits

17‘ULM’Perspectives:

Analogy:Trackteamwithankleweights:

Whatwouldhappenifwetookofftheweights?

Analogy:Ghettovs.suburbsHSexitexamscores:

Weknowthattheachievementswilldiffer,butthestoryshouldn’tstopthere.18‘ULM’Perspectives: Xfreakishtalent(WMcapacity,LTM,musicalability)Xfreakishaccomplishments(Hale,“Christopher〞)√normalsworkingwithintheirlimits√giveacquisitionthesamechanceithasinyoungerpopulations… -onecan’ttakeawayageeffects -onecanminimizeL1effects -onecanprovidebenignexternalconditions …andseewhathappens=>relevancetoclaims,assumptions;CPH/L2A,FDH,‘access’19UTCogSciPresentationL2endstateattainment:Approachultimateattainmentneutrally:deficits& differencesalongsideupperlimits FACTSaboutend-stateattainment,asmediatedbyageofacquisitionandageoftesting FACTORSthatconstrainvs.enableL2acquisition,andtheirnature

FALLACIESw/r/tendstate,e.g.CPH/L2A

Q:UnderDM:Evidenceformaturation-baseddifferences? Q:UnderULM:Whatcan(late)L2-dominantsdo?20Distinctions:

AoA≠AoT≠maturationalstateAoA=AgeofAcquisition(Immersion,Onset) =macro-variable,encompassinginteralia: -degreeofL1entrenchment -L1proficiency -stateofsystemplasticity -stateofcognitivedevelopment -degreeof(neuro-)cognitivedecline(adults) -suiteofneurobiologicalvariables

AoA=proxyforinitialstateofL2ANB:AoA-relatedeffectsNB:“Theagefactor〞=convenientbutunderspecificlabel21Distinctions:

AoA≠AoT≠maturationalstateAoT=AgeatTesting

=macro-variable,encompassinginteralia: degreeofL1entrenchment L1proficiency L2proficiency stateofsystemplasticity stateofcognitivedevelopment degreeof(neuro-)cognitivedecline[seeSupplements] suiteofneurobiologicalvariables

also:socio-psychologicalidentificationw/L2&L1

also:frequencyofL2/L1use

AoT=proxyforcurrentstateofL2knowledgeandprocessingNB:AoT-relatedeffects22AoTAdvancedAoT:

-MoreprofoundimpactinL2processingthaninL1processing.

L2processingmorevulnerablebecause:

-greaterrelianceonfluidintelligencethaninL1use -less-routinizedproceduresthaninL1useOpenquestion: -AoT(&AoA)-relatedeffects=lesssevereamongL2dominants?

23Distinctions:

AoA≠AoT≠maturationalstateMaturationalstate:>(vs.//vs.X)

//degreeofL1entrenchment //L1proficiency //L2proficiency

>stateofsystemplasticity

>stateofcognitivedevelopment

>degreeof(neuro-)cognitivedecline

>suiteofneurobiologicalvariables Xsocio-psychologicalidentificationw/L2&L1 XfrequencyofL2/L1use

//experientially

correlateswithaging AoA&AoT

>biologically

aging-related,pre-/post-‘maturation’AoA&AoT Xintrinsicallyunrelated

toaging AoTonly24DistinctionsUltimateAttainmentinL2 =endstate(asymptotic)knowledgeandprocessing

≠onlynativelikeness

=

anylevelatendstate,upto&includingnativelike25DistinctionsNature,causes&domainsofnon-nativelikeultimateattainment(Hopp,2007)Nature:REPRESENTATIONAL*COMPUTATIONAL /\ / | \Cause:impairment*L1 impairment*inefficiency*L1

[FT/FA]

/\ | | |Domain:module*interface parsing * info*inter-

routesintegrationference [FFF] [uF] [DP] [limcap][CM]

[SS] [MSI]26DistinctionsAge,endstate,upperlimits:

Computational(in)efficiency •=>defaulttolexis/plausibilityincomplexcomputations L1influence •developmental&atAoA/AoT •asalternativeto/complementtoimpairment Perceptualcomponentsofprocessing<->grammar

•detectionofuF •aspreconditionforinterpretation(e.g.inFrenchliaison)Nature:REPRESENTATIONAL*COMPUTATIONAL

/\ / | \Cause:impairment*L1impairment*inefficiency*L1

[FT/FA]

/\ | | |Domain:module*interface parsing*info*inter-

routesintegrationference [FFF] [uF] [DP][limcap][CM]

[SS] [MSI]27DistinctionsHeuristics:

UniversalLearnabilityversusSelectiveProcessability

-UniversalLearnability:anything

canbelearnedbysomeone -SelectiveProcessability:somethings

can’tbeprocessedbyanyone

28DistinctionsTheAoAfunction,shapes:

straightline stretched‘7’ inverted‘V’ stretched‘Z’TheAoAfunction,timingofdeflection:

coincidingwithknownmaturationalepochs coincidingwithagesunrelatedtomaturation

TheAoAfunction,steepness=>#ofnativelike-ers

29Slopepredictsincidenceofnativelikeness:

shallowslope=>highrateofnativelikenessAoA20YearsRangeofScoresofNativeControls

30Slopepredictsincidenceofnativelikeness:

steepslope=>lowrateofnativelikenessRangeofScoresofNativeControlsAoA20Years

31

FACTSofBiologicalAging

&theirrelationshiptoL2processing

bylateL2ers

32AgeandProcessing

SupplementI

Parketal.(2001)33AgeandProcessing

SupplementIbreak-out

Park(2000)34CognitiveAgingEffects Effectsinlanguageprocessing: •processingspeed •workingmemorycapacity •lexicalretrieval •linearoverAoT/AoA,startingat20yearsofage •priortoAoT/AoA:increasethendecline(inverted“V〞) plateauthendecline(stretched“7〞) •linkageofprocessingbehaviorstobiologicalaging (Bäckman&Farde,2005) =>L2processing constraintsoninputprocessingatAoA/AoT outputperformancedecrementsatAoT depressedlevelsofprocessingatL2endstate

35ConstrainingFACTORS

1-Neuro-biology/anatomy/chemistry/cognition:

post-puberty,withincreasingage(AoA&AoT): •‘useitthenloseit’(Pinker,1994)

•pathologicalincreasesincortisollevels •declinesinneurotransmitterlevels:ACH dopamine,etc.

SupplementII

•

decliningregionalbrainvolumes(Raz,2005)

SupplementIII

36BiologicalAgingEffects

Declinesinneurotransmitterlevels:ACH,dopamine,etc. SupplementII

NeurotransmitterdeclinesinL2processing: •varietyofcognitivefunctionsunderlyingL2processing -workingmemorycapacity&executivefunction -attention&inhibitoryprocesses(L1suppression) -coordination/proceduralizationinsyntax •linearoverAoT/AoA,startingat20yearsofage •priortoAoT/AoA: increase,thendecline(inverted“V〞) plateau,thendecline(stretched“7〞)

37BiologicalAgingEffectsDeclinesinregionalbrainvolume SupplementIII

EffectsinL2processing: •varietyofcognitivefunctionsunderlyingL2processing -executivefunction -LTM -coordination/proceduralizationinsyntax •linearoverAoT/AoA,startingat20yearsofage •priortoAoT/AoA: increasethendecline(inverted“V〞) possibleplateau(stretched“7〞) •notreliablelinkageofbehaviortobiologicalsources -effectsmoreassociatedw/neurochemistrythanw/structure -uncertaintimingofdecreasethresholds=> associatedcognitivedecrements

38ConstrainingFACTORS2-Cognitivedevelopment:

•Adultworkingmemorybandwidthletsintoomuchlinguisticinformationtoprocess atonce =>incompleteprocessingof,e.g., sequencesofmorphemes:“lessismore〞(Newport,various)

39ConstrainingFACTORS2-Cognitivedevelopment:

post-concreteoperations

•Analytic/metalinguistic/explicit input&learning •Literacy =>L2visàvisL1learning&processing:

?effortful ?inefficient √different[cognitive,neural]resources

40ConstrainingFACTORS3-L1entrenchment:L1representationsareincreasinglydefinedwithuse=>

•developingrepresentations/categories assimilatetoold(Flege,various) •competitionbetweenoldanddeveloping representations(MacWhinney,various)

•[Hebbian]learninginhibitsrelatednew learning(Elman,various)

41FacilitatingFACTORSEnablingvia 1-Subtractionofconstraint •minimizeL1influenceviaL1 attritionorL2dominance [Moretocome]

42FacilitatingFACTORSEnablingvia 2-Offsettingtheeffectsoflimitingfactors •trainingonL2perception •trainingonL2pronunciation

43FacilitatingFACTORSEnablingvia: 3-Individualvariation •aptitudecomponents (phonological)workingmemory •health/genetic/lifestyle hypertension:inverted“U〞function ACH,testosterone,estrogen,dopamine, cortisol[early&late] •attitude&affect motivation;L2‘identity’;‘passingfor’ •L2use/practice/rehearsal/education

44FacilitatingFACTORSNB:

Somefactorstrumpotherse.g., neurobiology=irrelevantiflow desireforattainment;v. •passingforanative •IDwithL2culture& speakers45FacilitatingFACTORSNB:

Distinguishnecessaryfromsufficientconditions:Agivenfactormaybenecessarybutnotsufficientfornativelikeattainment46FACTSofUpperLimits:

candoUncontroversiallyagivenlate(AoA>12)L2learner

can:performlikemonolingualsacross multiplecomplexbehavioralmeasuresofgrammaticalknowledge&lexicalknowledge& globalpronunciation can:performlikemonolingualsonarangeof brain-basedmeasuresofL2processinge.g.,ERPcomponents,regionalbrainactivity[moretocome]47FACTSofUpperLimits:

cannotdoUncontroversiallylatelearnerGROUPS

cannot:performlikemonolingualson ‘challenging’onlineandofflinetasks/structures/items;variousprocessing tasksinvolvingparsing,suprasegmental perception,etc.

48FACTSofUpperLimits:

cannotdo?Controversially

agivenlateL2learner

cannot:performlikemonolinguals oncertainon-lineprocessingtasksinvolvingsentenceparsing,suprasegmentalperception, etc.(quantitative&qualitativedifferences)

49Aside:AoAgradient

andrateofnativelikeness

50Slopepredictsincidenceofnativelikeness:

shallowslope=>highrateAoA20YearsRangeofScoresofNativeControls

51Slopepredictsincidenceofnativelikeness:

steepslope=>lowrateRangeofScoresofNativeControlsAoA20Years

52FACTORSunderlyingFACTSFACTORSthatmodulateobservedslopes(FACTS):

•FrequencyofL2use •DegreeofL1entrenchment •DegreeofL1vs.L2dominance •Neuro-biological/cognitive/anatomical/chemical state •IdentificationwithTL’ers •Motivationtolearn/‘passfor’nativeTL’er •FL/L2learningaptitude,e.g.,pitchperception, auditorydiscrimination •Sub-domainoflanguagee.g.,pronunciation.vs. agreement •Generalcognitiveabilities/aptitudes,e.g., phonologicalworkingmemory •Felicitousfeature-wiseL1-L2pairing •‘Easy’vs.‘hard’tasks(e.g.,off-linevs.on-line)

53FACTORSunderlyingFACTS PositedFACTORS/mechanismsunderlyingFACTSofageeffectsinL2processing=consistentwithcommonsenseandempiricalresearch

EachisplausiblyatworkinsomefashioninL2AContributionofeachmayvaryovertimecourseof

L2learninganduseContributionofeach

maydifferfromindividualtoindividualIntheaggregate,someaccountformorevariancethanothers54FACTORS,FACTS,FALLACIES PositedFACTORS/mechanismsunderlyingFACTSofageeffectsinL2processing=consistentwithcommonsenseandempiricalresearchEachisplausiblyatworkinsomefashioninL2A FALLACY:thereisasinglesourceofageeffectsContributionofeachmayvaryovertimecourseofL2learning/use FALLACY:contributionsarestaticovertimeContributionofeachmaydifferfromindividualtoindividual FALLACY:onesizefitsall(genetic,deterministicaccount) FALLACY:nothingonecandoaboutslopeofdeclines FALLACY:weshouldstudygroups(and“generalfailure〞)Intheaggregate,someaccountformorevariancethanothers FALLACY:assumenointeractionbetween/amongfactors55THEAOAFUNCTION

INEND-STATEL2ATTAINMENT

(Processing&Knowledge)

56SuccessfulAging

Cotman(2000)57AgefunctionsinL2A…

Context:

Twotypesofevidencepro/contraCPHinL2A: 1)late-learnernativelikenessatendstate

(v.supra&infra).

Long(1990):

asinglelatelearneratnativelikelevelswouldfalsifyCPH/L2A

learningcircuitrynolongerplasticbecauseneurobiologicalmaturationiscompleted

58AgefunctionsinL2A…

Context:

Twotypesofevidencepro/contraCPHinL2A:

2a)characteristicsofagefunction

Pulvermüller&Schumann(1994):

unboundedAoAeffectspastpubertywouldfalsifyCPH/L2A

ongoingageeffectsareinconsistentwithpresumedcompletionofneurobiologicalmaturation

59AgefunctionsinL2A…

Context: Twotypesofevidencepro/contraCPHinL2A:

2b)characteristicsofagefunction

Johnson&Newport(1989):

functionlevelsoffatAoA17;supportsCPH/L2A

ongoingageeffectsareinconsistentwithpresumedcompletionofneurobiologicalmaturation

Recall:biologysaidtobedeterministicallylinkedtonon-nativelikenessamonglateL2learners(v.supra).

60AgefunctionsinL2A CanCPH(s)forL2AbereconciledwiththeFACTS,i.e.withobservedgeometry&timingofAoA-attainmentfunctions?

Observedgeometryofdecliningattainment

-functionmaybestraightline,curvilinearordiscontinuous; inallcasesdeclinespersistoverAoA Observedtimingofstartofdecline

-infancy -childhood -aroundpuberty -postpuberty

Observedtimingofendofdecline(?)

61ObservedAoA-

L2attainmentdistribution

(Flegeetal.,1995)62ObservedAoA-

L2attainmentdistribution

(Flegeetal.,1999)63ObservedAoA-

L2attainmentdistribution

(Flegeetal.,1999)64ObservedAoA-

L2attainmentfunction

(Flegeetal.,1999)65

ObservedAoA-

L2attainmentfunction

(Birdsong&Flege,2000)

AccuracyoverAoA66Birdsong&Flege(2000)67Birdsong&Flege(2000)68ObservedAoA-

L2attainmentfunctionNegativecorrelationofAoAandattainmentmeasuresOverfullAoAspan:Significantlinearcorrelations.Range:-.45to-.77;median-.64.69ObservedAoA-

L2attainmentfunction

OverfullAoAspanvs.disaggregatedanalyses

1.J&N‘89=significantoverall;sig.early,randomlate

2.B&M‘01

=significantoverall;ceilingearly,sig.late70ObservedAoA-

L2attainmentfunction

Overallvs.disaggregatedanalyses

3:

DeKeyser(2000)

=significantoverall;nsearly,nslate71ObservedAoA-

L2attainmentfunction

SummaryofFACTS

•OverallAoA: -significantdeclines -persistindefinitely(notbounded,no‘period’) •LateAoA: -declines:typicallysignificant •EarlyAoA: -Inconsistentfindings:some functionsflat,some random,somedecliningabinitio

Smallsamplesize=>cautionininterpretation;restrictsapplicablemodels72TheoreticalCPs73TheoreticalCP74TheoreticalCPs75AgefunctioninL2A=criticalperiodfunction?Definitionallogic:

ifcriticalperiod,then:

•Finite,boundedeffects,confinedtoaperiod

-(minimalcriterion:discontinuityintheagefunction)Ifattainmentisconditionedbymaturation,then:•Theagefunctionshouldlookdifferentpre-vs.post-maturation

-discontinuityissynchronizedwithendof somedevelopmentalepoch,pre-maturation -classicalL2literature:discontinuitysynchronizedwithend ofmaturation76AgefunctioninL2A=

criticalperiodfunction?

(highlysimplifiedschematics) Stretched“7〞Stretched“L〞 ceiling,thendeclinedecline,thenfloor77Maturationally-BasedL2CriticalPeriod

GeometricandTemporalFeatures

àla(J&N1989;Pinker,1994)

1=

peaksensitivity

2=

beginningofoffset

3=

endofoffset

4=

baselinesensitivity

NB:

3

coincideswithendofmaturationNB:

4

ageeffectsdonotpersist

1234STRETCHED“Z〞(Johnson&Newport,1989)(Pinker,1994)78STRETCHED“Z〞

(Newport,1991)79Johnson&Newport(1989)

[Stevens(2004)rendering]

80

Johnson&Newport(1989)

EarlyarrivalsLatearrivalsFlatsegmentatrightendofstretched“L〞(likestretched“Z〞inearlierslide)=FALLACY81AgefunctioninL2A=criticalperiodfunction? Stretched“L〞:littleevidenceforflooreffect Stretched“7〞:evidenceforceilingeffect;butcanpersistuptoAoA=27.5years(B&M2001)82AgefunctioninL2A=criticalperiodfunction? Minimalnecessaryfeatureofgradient:

Discontinuityatsomepoint[notbeyondendofmaturation]intheoverallagefunction.

(Stevens,Bialystok&colleagues,interalia)83 Singlelinearmodelvs.“elbow〞model

Re-analysisofresultsofFlegeetal.(1995)

(thankstoJan-PieterdeRuiter)84

FALLACY:anydeflection=CPevidence

1-non-linearity/discontinuitymustbeobservedinmodels otherthandisaggregation

2-mustconsidermagnitudeofdeflection

3-deflectionpointmust//hypothesizedsourceofeffect85AgefunctioninL2A=criticalperiodfunction?-LinearmodelappliedoverallAoA&supported

-Othermodels: -variabletimingofdeclines -milddeclines,milddeflectionsoffstraightline (elbowpossiblymorepronouncedin“7〞thanin“L〞)

-Allmodels: -variableslopes -persistentageeffectspostmaturation

86AgefunctioninL2A=criticalperiodfunction? Conceptual: -Maturationconstrainstheoffsetofageeffects?(“L〞 or“Z〞geometry) -Maturationdeterminestheonsetofageeffects?(“7〞 geometry) -“Maturationaleffects〞functions=consistentwithother plausiblemechanisms/factorsindecliningattainment -Ifmaturationisthe(only)sourceofageeffects,there shouldbenoL1effects(cf.J&N1989vsB&M2001)

87AgefunctioninL2A=criticalperiodfunction? √Evidenceof“7〞geometryi.e.“windowofopportunity〞,“optimalage〞=ceiling[‘agenon-effect’] √Evidenceof“7〞geometrywithwindowendingpriortolateadolescence[endofwindowdueto?]

88AgefunctioninL2A=criticalperiodfunction? X“7〞geometryofceiling(‘windowofopportunity’)observedinoneinstancetoextendpastendofmaturation(AoA=27.5) XLittleevidenceoffloorin“L〞or“Z〞geometryatanyAoA

89AgefunctionsinL2A…

Varyingeometry:shape

-linear -curved,discontinuous -threshold-with-cascade,etc. -BUTinvariablydeclinespersistoverAoA Varyingeometry:slope

-slopeofdeclinemodulatedbyexternalfactors (e.g.,L1-L2pairing,contactwith/useofL2) -slopeofdeclinemodulatedbyinternalfactors (e.g.,motivation,identification,aptitude)

90AgefunctionsinL2A… Varyintimingofdecline

-infancy -childhood -aroundpuberty -postpuberty

Geometryandtimingvarybylanguage(sub)domain&task

-morphosyntacticknowledge(surface/abstract) -pronunciation -perception -on-lineparsing

+featurestherein+task

91AgefunctionsinL2A Whatmechanismsarecompatiblewithobservedgeometry&timingofAoA-attainmentfunctions?

Shape,slope,andtimingmaybe‘consistentwith’: -cognitivedevelopmentalstateaccounts -neurologicaldevelopmentaccounts -neurocognitivedeclineaccounts -entrenchmen