2009 Effects of age on second language acquisition

CaliforniaLinguisticNotesVolumeXXXIVNo.2Spring,2009ImanTohidianUniversityofKashan,IranEzatollahTohidianUniversityofKashan,IranEffectsofageonsecondlanguageacquisitionAbstract.Therearemanydifferencesamongsecondlanguagelearners.Infirstlanguageacquisitionbychildren,individualdifferences(e.g.acrossgendersorthelanguagebeinglearned)arelargelyovershadowedbystrikingsimilaritiesintermsofnaturalstagesandultimateattainment.However,insecondlanguageacquisition,individualdifferenceshavemoreofanimpactonthesecondlanguagelearningprocess,andtheirrolehasthusreceivedconsiderableattentioninrecentyears.Learners'beliefsandaffectivefactorsarelikelytohaveadirecteffectonsecondlanguagelearning,buttheythemselvesmaybeinfluencedbyanumberofgeneralfactorsrelatingtolearners'abilityanddesiretolearnandthewaytheychoosetogoaboutlearning.Oneofthoseimportantareasofdifferenceamongsecondlanguagelearnersisage.Wenowturntoadiscussionoffourmaineffectsofageonsecondlanguageacquisition.Keywords:firstlanguageacquisition;secondlanguageacquisition;affectivefactors;age;learners'beliefs;native-speakerproficiency1.IntroductionAnindividualdifferencethatisbelievedtoplayakeyroleinsecondlanguagelearningisage.Itiscommonlythoughtthatyoungerlanguagelearnersaremoresuccessfulandindeedresearchershavefoundarelationshipbetweenageofacquisitionandultimateattainmentinatleastsomeaspectsofthesecondlanguage,withageshowingitselftobethestrongestpredictorofsuccess.ThisissupportedbytheCriticalPeriodHypothesis.OriginallyCaliforniaLinguisticNotesVolumeXXXIVNo.2Spring,20092discussedinthelate1960sbyEricLenneberg,thishypothesisstatesthatlanguageacquisitionmustoccurbeforepubertyinorderforthespeakertoreachnative-likefluency.PenfieldandRoberts(1959),forexample,arguedthattheoptimumperiodforlanguageacquisitionfallswithinthefirsttenyearsoflife,whenthebrainretainsitsplasticity.Initially,thisperiodwasequatedwiththeperiodtakenforlateralizationofthelanguagefunctiontotheleftsideofthebraintobecompleted.Workonchildrenandadultswhohadexperiencedbraininjuriesoroperationsindicatedthatdamagetothelefthemispherecausedfewspeechdisordersandwasrapidlyrepairedinthecaseofchildrenhutnotadults(Lenneberg1967).Althoughsubsequentwork(forexample,Krashen1973;Whitaker,Bub,andLeventer1981)haschallengedthepreciseagewhenlateralizationtakesplace,resultingindoubtsabouttheneurologicalbasisofthecriticalperiodhypothesis,theagequestionhascontinuedtoattracttheattentionofresearchers.ThiscontroversycentresonbothwhethertherearesignificantdifferencesinL2learningaccordingtoage,andalsoonthetheoreticalexplanationsforthosedifferenceswhichresearchersclaimtohavefound.AsLarsen-FreemanandLong(1991)pointout,however,theageissueisanimportantonefortheorybuildinginsecondlanguageacquisitionresearch,foreducationalpolicy-making,andforlanguagepedagogy.Ifitcanbeshownthatolderlearnersaredifferentfromyoungerlearners,theclaimthatadultshavecontinuedaccesstoUniversalGrammariscalledintoquestion.Ifitcanbeshownthatyoungerlearnersdobetterthanolderlearners,thecaseforanearlystartinforeignlanguageeducationisstrengthened.Ifitcanbeshownthatchildrenlearnindifferentwaystoadults,languageteacherswillneedtoidentifydifferentapproachesandtechniquestosuitthetwokindsoflearners.Inordertountangletheresearchresults,itishelpfultoconsideranumberofseparatebutrelatedquestions:•Whateffectdoesagehaveontheprocessesofsecondlanguagelearning?•Whateffectdoesagehaveontherateofsecondlanguagelearning?CaliforniaLinguisticNotesVolumeXXXIVNo.2Spring,20093•Whateffectdoesagehaveonlearners'levelsofsecondlanguageachievement?•Whateffectdoesagehaveonlearners'abilitytoachievenative-speakerlevelsofproficiency?2.TheeffectsofageontheprocessofsecondlanguageacquisitionTherehavebeenfewstudiesoftheeffectsofageontheprocessofsecondlanguageacquisition.ThemorphemestudiesshowedthattheorderofacquisitionofagroupofEnglishmorphemeswasthesameforchildrenandadults(Bailey,Madden,andKrashen1974;Fathman1975).However,conclusionsbasedonthemorphemestudiesarecircumspectgiventheirmethodologicalproblems.Studieswhichhaveinvestigatedthesequenceofacquisitionintransitionalstructuressuchasnegativesandinterrogativesarenotsubjecttothesamemethodologicalstrictures,however.Theyshowthatadultsgothroughthesamestagesofacquisitionaschildren(forexample,Cancinoetal.1978).Age,therefore,doesnotappeartoaffectthegeneraldevelopmentalpattern.ByfarthemostdetailedstudyoftheeffectsofageontheacquisitionprocessisHarley's(1986)investigationofearlyandlateimmersionprogrammes.Harleyfoundremarkablysimilarpatternsinthetwogroups'acquisitionoftheFrenchverbphrase.Forexample,thetwoagegroupsgenerallymadesimilartypesoferrorsandbothgroupstendedtousetherelativelyunmarkedFrenchverbformsmoreaccuratelythanthemarkedforms.Afewdifferenceswerenotedbutthesewereminor,andHarleydidnotfeelthattheyconstitutedevidenceofdifferentmentalprocesses,arguinginsteadthatthedifferencesreflectedvariationsinthesecondlanguageinputtowhichthelearnerswereexposed.Processdifferencesmayoccurinsecondlanguagepronunciation,however.Riney(1990)reviewedliteraturerelatingtowhetherlearnersdisplayapreferencefo