克拉申二语习得五假说

Krashen'sfivehypothesis——Krashen'sMonitorTheoryFivebasichypotheses:TheAcquisition-LearningHypothesisAcquisition:naturally,subconscious,informal,Learning:consciously,formal,'knowaboutthesecondlanguage,analysisandcorrectionoferrorsformallyandexplicitlyaddressed.Krashensupportsthisclaimasfollows:therecanbeacquisitionwithoutlearning.Competentlanguagelearnersmayspeakthelanguagewithoutconsciouslyknowingtherules.therearecaseswherepeoplecan'know'arulebutdonotuseitinnormalinteraction.inanycase,nobodyknowsalltherulesofalanguage.GrammaticalexplanationseveninlanguagesaswidelystudiedasEnglishdonotcoverthelargelyunconsciouslyknowledgeofanative-speaker.Itoftentakeslinguistsyearstodescriberuleswhicharerelativelyeasilyacquired(Ellis1985).AcquisitionandLearningarenotdefinedby'where'asecondlanguageoccurs.Formallearninginthestreet.Thedistinctionisacentralideaineducationtheory:betweendeductive(推理:fromgeneraltoparticular)andinductive(归纟内［approaches;classroomandnaturalisticlearning;formalandinformallanguagelearning.TheNaturalOrderHypothesisGrammaticalstructuresareacquiredinapredictableorderforbothchildrenandadults,irrespectiveofthelanguagebeinglearnt.Somerulestendtocomeearlyandotherslate.Theorderdoesnotappeartobedeterminedsolelybyformalsimplicityandthereisevidencethatitisindependentoftheorderinwhichrulesaretaughtinlanguageclasses.Whenalearnerengagesinnaturalcommunication,thenthestandardorderwilloccur.TheMonitorHypothesisTheMonitorisaneditingdevicethatmayoperatebeforelanguageperformance.UtterancesmaybemodifiedbybeingacteduponbytheMonitoroflearntknowledge.Sucheditingmayoccurbeforethenaturaloutputofspeech;itmayoccuraftertheoutputviaacorrectingdevice.Krashensuggeststhatmonitoringoccurswhenthereissufficienttime,whenthereispressuretocommunicatecorrectlyandnotjustconveymeaning,andwhentheappropriaterulesofspeechareknown.Putittheotherway:theremustbetimeforaspeakertouseconsciousruleseffectively.Normalconversationdoesnotallowforthismonitoring.timealoneisnotenough.Thespeaker'sattentionmustalsobefocusedonForm.thespeakermustknowtherulebeforethemonitorcanbeused.Examplesincludeknowingthecorrecttensetouse,whentousethethirdorfirstpersonandrulesaboutplurals.Thishypothesishasbeencriticizedforbeinguntestableandforalackofsupportiveresearchevidence.TheInputHypothesisToexplainhowlanguageacquisitionoccurs,Krashenproposesthatwhenlearnersareexposedtogrammaticalfeaturesalittlebeyondtheircurrentlevel,thosefeaturesare'acquired'.Krashenemphasizesthat'acquisition'istheresultofcomprehensiblelanguageinputandnotoflanguageproduction.Inputismadecomprehensiblebecauseofthehelpprovidedbythecontext.Ifthelanguagestudentreceivesunderstandableinput,languagestructureswillbe,accordingtoKrashen,naturallyacquired.ForKrashen,theabilitytocommunicateinasecondlanguage'emerges'ratherthanisdirectlyputinplacebyteaching.Secondlanguageissaidtobecausedbytheprocessofunderstandingsecondlanguageinput.Krashenlistsanumberoflinesofevidencetosupporttheinputhypothesis:Othesilentperiod:thisisbasedonthefactthatchildreninanL2situationsometimesremainsilentforseveralweeks.Similarly,youngchildrenareexposedtotheirmothertongue(andobviouslyunderstandit)beforetheybegintospeak.Oagedifference:youngerlearnersmaygetmorecomprehensibleinputbecausetheytendtoengagein'here-and-now'interactions.Olderlearnersmaymakefasterprogressinitially,however,becausetheyareexposedtomorecomprehensibleinputthankstotheirbroaderworldknowledgeandbecauseofthecommunicativestrategiestheyhavealreadydevelopedintheirL1.Otheeffectofexposure:themorelearnersareexposedtocomprehensibleinput,themoretheirlanguageproficiencydevelops.Learnerswhodonothaveaccesstocomprehensibleinputareheldupintheirdevelopment.Oimmersion,bilingualandshelteredlanguageteaching:studentsintheseprogramslearneffectivelybecausetheyreceivecomprehensibleinputwherethefocusisonthesubjectmatterbeingtaughtratherthantheformofthelanguage.Osimplecodes(caretakerspeech,motherese,foreignertalk,etc.)provideidealinputbecause(a)theyareusedtocommunicatemeaning,notform,(b)theyareroughlytunedtothelearners'currentleveloflinguisticcompetence,andtheyfollowthe'here-and-now'principlewhichhelpsthelearnersunderstand.Otheeffectsofinstruction:instructionishelpfulwhenitistheprimarysourceofcomprehensibleinput.Formalinstructionisonlyhelpfulbecauseitissourceofcomprehensibleinput.Methodsthatfocusoncomprehensibleinputareassumedtobesuperiortogrammar-basedordrill-basedmethodswhichfocusonlearningInputislanguagewhichalearnerhearsorreceivesandfromwhichhe/shecanlearn.Intakeisinputwhichisactuallyintegratedintothelearner'sinterlanguage.'speakersacquireIanguageinonlyoneway-byunderstandingmessages,orbyreceiving'comprehensible(orbetterstillcomprehended)input'•…Wemovefromi,ourcurrentlevel,toi+1,thenextlevelalongthenaturalorder,byunderstandinginputcontainingi+1'.TheAffectiveFilterHypothesisAnaffectivefilterwasproposedbyDulay&Burt(1977)withtheideathatthereisafilterthatdetermineshowmuchapersonlearnsinaformalorinformallanguagesetting.Thefiltercomprisesaffectivefactorssuchasattitudestolanguage,motivation,self-confidenceandanxiety.Thuslearnerswithfavorableattitudesandself-confidencemayhave'alowfilter'withconsequentefficientsecondlanguagelearning.Thosewithunfavourableattitudesand/orhighanxietyhave'highfilters'andsotheinputofsecondlanguagelearningmaybeblockedorimpeded.TheaffectivefilterproposedbyKrasheninfluencestherateofdevelopmentinsecondlanguagelearningandthelevelofsuccessinbecomingbilingual.Krashen:comprehensibleinputmaynotbeutilisedbysecondlanguageacquirersifthereisa'mentalblock'thatpreventsthemfromfullyprofitingfromit.Iftheaffectivebarrierisdown(i.e.whenthelearnerismotivated,confident,andnotanxious),comprehensibleinputreachestheLanguageAcquisitionDevice.Theaffectivefilterhas4functions:itdeterminestheselectionoflanguagemodels;itdetermineswhichpartofthelanguagewillbeattendedtofirst;itdetermineswhenlanguageacquisitioneffortsshouldcease;itdeterminesthespeedofacquisitionSummaryofthe5hypothesis'Peopleacquiresecondlanguagesonlyiftheyobtaincomprehensibleinputandiftheiraffectivefiltersarelowenoughtoallowtheinput'in'.Whenthefilteris'down'andappropriatecomprehensibleinputispresented(andcomprehended),acquisitionisinevitableItis,infact,unavoidableandcannotbeprevented-thelanguage'mentalorgan'willfunctionjustasautomaticallyasanyotherorgan'(Krashen1985:4)Krashen'stheoryappliedtotheclassroom(discuss)thegoalofteachingmustbetosupplyunderstandableinputinorderforthechildoradulttoacquirelanguageeasily.Agoodteacherthereforeissomeonewhocontinuouslydeliversatalevelunderstandablebythesecondlanguagespeaker.Justasfather/mothertalk(motherese)helpstheyoungchildtoacquirethefirstlanguagebyasimplifiedandcomprehensiblelanguage(andnonverballanguage),soaneffectiveteacherissaidtofacilitatesecondlanguagelearningbyensuringaclosematchbetweenthelevelofdeliveryandthelevelthatisunderstandable.teachingmustpreparethelearnerforreallifecommunicationsituations.Theclassroomneedstoprovideconversationalconfidencesothat,whenintheoutsideworld,thestudentcanbothlinguisticallycopeandcontinuelanguagelearning.Languageandcommunicationarethetwosidesofthesamecoin.Teachersshouldprovideopportunitiesforcommunication.McNamara(1973)hasarguedthat'thereallyimportantpartofmotivationliesintheactofcommunication.Rossier(1975)alsoemphasizestheimportanceofadesiretocommunicate,arguingthatwithoutthis,students'motivationmaynotbeeffective.ItistheneedtogetmeaningsacrossandthepleasureexperiencedwhenthisisachievedthatprovidesthemotivationtolearnanL2.Teachersalsoshouldprovideopportunitiesforgroupwork.Teachersshouldtrytoensurethatstudents'interestisengenderedasaresultofagoodrapportwiththelearners.AsFinocchiaro(1981)putsit:Themomentoftruth---theenhancementofmotivation---occurswhentheteacherclosestheclassroomdoor,greetshisstudentswithawarm,welcomingsmile,andproceedstointeractwithvariousindividualsbymakingcommentsoraskingquestionswhichindicatepersonalconcern.teachersmustensurethatlearnersdonotbecomeanxiousordefensiveinlanguagelearning.ThisrelatestotheAffectiveFilterhypothesis.Theconfidenceofthelearnermustbeencouragedinalanguageacquisitionprocess.Whenalearnerisrelaxed,confidentandnotanxious,thentheinputoftheclassroomsituationwillbemoreefficientandeffective.Ifteachersinsistonchildrenconversingbeforetheyfeelcomfortableindoingso,orateacherconstantlycorrectserrorsandmakesnegativeremarks,thelearnermayfeelinhibitedinlearning.formalgrammarteachingisoflimitedvaluebecauseitcontributestolearningratherthanacquisition.Onlysimplerulesshouldbelearnt.Complexruleswillnotbeusedconsciouslyorunconsciouslybythelanguagelearner.Therefore,thereappearslittletobegainedfromformallyteachingtherulesofasecondlanguage.errorsshouldnotbecorrectedwhenacquisitionisoccurring.Theymaybecorrectedwhenthegoalisformallearning.Errorcorrectionisvaluablewhenlearningsimplerulesbutmayhavenegativeeffectsintermsofanxietyandinhibition.ForKrashen,a'NaturalApproach'isrequiredinlanguageteaching.TheNaturalApproachisverydifferentformtraditionalgrammarteachingandlanguagelaboratorytypesofapproach.Itsmaintenetsareasfollows:communicativeskillsshouldbetheaimofthegoodlanguageclassroom;comprehensionoflanguageshouldprecedeproduction(listeningshouldprecedespeaking);speakingandthenwritingwillemergewhenthelanguagelearnerisreadyandshouldnotbeforced;acquisitionratherthanformallearningiscentralingoodlanguagelearning;andtheaffectivefilterneedstobekeptlow.ProblemswiththeMonitorModelMcLaughlin(1987)criticisesKrashenfornotdefininghistermswithenoughprecisionandforbasinghistheoryonweakempiricalevidence.Thetheory,furthermore,failstomakeclearpredictions.McLaughlinliststhefollowingproblems:★thelearning-acquisitiondistinctionisnotclearlyenoughdefinedtoallowforempiricaltesting.Leakagefromlearnttoacquiredseemsnotonlypossiblebutwell-substantiated.When'learnt'knowledgeisautomatisedthroughpracticeitbecomes'acquired'(i.e.,availableforspontaneoususe).★variationisexplainedintermsofmonitoredandunmonitoredperformanceandthereisnoprovisionforpartialmonitoring(i.e.theMonitoriseitheronoroff).Sociolinguisticresearch,however,showsthatallspeakersengagein'small-m'monitoringinthattheirspeechvariesonacareful-non-carefulcontinuumaccordingtothelevelofattentiontoform.Thisattentiontoformdoesnotnecessarilyimplytheuseofarticulatedrulesofusage.★Krashen'scaseforthenaturalorderhypothesisisbasedlargelyonmorphemestudieswhicharequestionableandprovidelittleinformationabouttheprocessofacquisitionbecausetheyfocusonfinalform(i.e.theproduct).★theinputhypothesisisuntestablebecausenodefinitionisgivenof'comprehensibleinput'oroftheconstructsiandi+1.Thehypothesisalsofailstoexplaintheeliminationofincorrectintermediateformsinthelearner'sinterlanguageandprovidesnowayofdistinguishingbetweendifferentinstructionalmethodsbecauseeach,ifeffective,canbearguedtoprovidecomprehensibleinput.Thereseemsacontradictionbetweentheemphasisplacedonthecrucialcomponentof'roughtuned'input(theexternalenvironment)andthenaturalorderhypothesis(aninternalprocess).★theaffectivefilterhypothesisisvagueanddoesnotexplainhowthefilterdevelopsorwhy,forexample,itaffectslanguageacquisitioninadultsbutnotinchildren.Affectivitymayjustaswellinfluencealearner'sconsciouslearningbyinterferingwithoraidingconcentration,memory,hypothesisformation,orassiduity.△manyresearchersagreewithKrashenonbasicassumptionssuchastheneedtomovefromgrammar-basedtocommunication-basedinstruction,theroleofaffectivefactorsinlanguagelearningandtheimportanceofacquisitionalsequencesinsecondlanguageacquisition.Thetheoryhas,nevertheless,beencriticizedbecauseittriestoachievetoomuchandmakesassertionswhichcannotbeprovedor,indeed,contradictedbyempiricalevidence.