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Literaturereview

Theoreticalissues

Leveltsspeechproductionmodel

Leveltproposedapowerfulmodelofspeechproductionin1989.Hediscriminateddeclarativeknowledgefromproceduralknowledgeandcontrolledprocessingfromautomaticprocessing.Declarativeknowledgeincludessituationknowledge,encyclopedicknowledge,especiallydiscourseknowledgeandconceptualandlexicalknowledge.Proceduralknowledgeisthebasisofsomeexperiencedperformancessuchasthefluentspeaking.(Zhang,2002)FourcomponentsformLevelt`sspeechproductionmodel:aconceptualizer,aformulator,aknowledgecomponent,anarticulatorandaspeech-comprehensionsystem.Anditsadvantageconsistsintheconcordancyofthedifferentpartsoftheproductionprocess,otherthanbeinglimitedtodifferentpartsoftheproductionprocess.Threecomponents,theformulator,theconceptualizer,andthearticulatorismostclosetooraloutput.Intheformulator,thespeakerchoosesacceptablelanguageformsfromthementallexicontotranslatepre-verbalmessagesintophonologicalplans.Intheconceptualizer,thespeakerchoosesthedeclarativeknowledgerelatedtothepurposesandorderstheinformationforpre-verbalmessage.Theninthearticulator,theactualspeechisrealized.Insummary,accordingtoLevlet`sspeechproductionmodel,theinformationcouldbeprocessedatthesametimeandthehigh-levelprocessingislessautomaticthanthelow-levelprocessing.Mostofall,onaccountoftheessenceofworkingmemoryandthespeedwithwhichspeechisnormallyproduced,Leveltindicatesthatfluentspeechproductionrequiresproceduralknowledgeandautomaticprocessing.(Zhang,2002)

Workingmemorycapacity

Workingmemoryreferstothelimitedcapacitycognitivesystemresponsibleforbothstorageandprocessingofinformationduringtheperformanceofcomplexcognitivetasks(McLaughlinHeredia,1996;DanemanCarpenter,1980;Baddeley,1986).In1974,BaddeleyandHitchproposedthemulti-componentmodelofworkingmemory.Therearethreerelativelyindependentcomponentsofworkingmemory:theyarephonologicalloop,visuo-spatialsketchpadandcentralexecutive(Baddeley,1986).Thecentralexecutivesystemisthecoreofworkingmemory,alsoacontrolsystemwithlimitedcapacity.WMisalsocalledshort-termstoreorshort-termmemory,primarymemory,immediatememoryandreferstothetemporaryprocessingandstorageofinformation.Therehavebeennumerousmodelsproposedregardinghowworkingmemoryfunctions,bothanatomicallyandcognitively.OneofthemostimportantofthemisBaddeleyandHitchsmulti-componentmodel.

AccordingtoBaddeley,workingmemoryisthecapacity-limitedcognitivemechanismthatenablesustotemporarilymaintainseveralpiecesofinformationinmindwhilecomprehending,thinking,speaking,anddoing.WecanreasonablyinferthatworkingmemoryplaysaquitesignificantroleincognitiveactivitiesandthusexpectdifferencesbetweenEFLspeakerswithhighandlowworkingmemorycapacity.

Planning

IntheColinsAdvancedDictionary,planningisdefinedasthecognitiveprocessofthinkingaboutwhatyouwilldointheeventofsomethinghappening.D'Ely(2004)arguesthatalthoughplanningisessentiallyacognitiveprocesswhichisinherenttotheactofspeaking,itevolvesintoametacognitiveprocesswhenitisusedstrategicallybythelearner.Therefore,D'Ely(2004)definesstrategicplanningasaproblem-solvingactivitythatprovideslearnerstheopportunitytoexertsomecontroloverwhattheyknowtowardsachievinggainsinoralperformance.

Planningisaproblemsolvingactivity,andaccordingtoHambrickandEngle(2003),aproblemisagoalwhichisnotinstantaneouslyachievableandwhosemostprominentfeatureisthatalthoughtheinitialstateandthetargetareclear,howtoconverttheinitialstateintothetargetstateisuncertain.HambrickandEngle(2003)claimthatproblemsolvingactivitiesrequiretheabilitytomaintaingoals,actionplans,andothertask-relevantinformationinahighlyactivatedandaccessiblestate,andwhennecessary,toinhibitactivationofirrelevantordistractinginformation.SeveralstudieshaveinvestigatedtheimpactofplanningonL2performance.Ingeneral,studieshaveshownapositiveimpactofplanningonperformancebutgainsdonotseemtobeachievedsimultaneouslytothesameextentforthedifferentaspectsofperformancefluency,accuracyandcomplexitysincetheseaspectscompeteforlearners'limitedcapacityattentionalresources(FosterSkehan,1996;Mehnert,1998;Guar,2009).