The-Language-Acquisition-Device-(

TheLanguageAcquisitionDevice(LAD)isapostulatedorganofthebrainthatissupposedtofunctionasacongenitaldeviceforlearningsymboliclanguage(i.e.,languageacquisition).FirstproposedbyNoamChomsky,theLADconceptisaninstinctivementalcapacitywhichenablesaninfanttoacquireandproducelanguage.Itiscomponentofthenativisttheoryoflanguage.Thistheoryassertsthathumansarebornwiththeinstinctorinnatefacilityforacquiringlanguage.ChomskyhasgraduallyabandonedtheLADinfavourofaparameter-settingmodeloflanguageacquisition(principlesandparameters).ChomskymotivatedtheLADhypothesisbywhatheperceivedasintractablecomplexityoflanguageacquisition,citingthenotionofinfiniteuseoffinitemeansproposedbyWilhelmvonHumboldt.Atthetimeitwasconceived(1957–1965),theLADconceptwasinstrictcontrasttoB.F.Skinner'sbehavioralpsychologywhichemphasizedprinciplesoflearningtheorysuchasclassicalandoperantconditioningandimitationoverbiologicalpredisposition.TheinteractionisttheoryofJeromeBrunerandJeanPiagetlateremphasizedtheimportanceoftheinteractionbetweenbiologicalandsocial(natureandnurture)aspectsoflanguageacquisition.Differingfromthebehavioristswhoemphasizetheimportanceofsocialinteractionsinlanguageacquisition,Chomsky(1965)setoutaninnatelanguageschemawhichprovidesthebasisforthechild’sacquisitionofalanguage.Theacquisitionprocesstakesplaceinaninfantsmindbecauseofthismentalorganwhichenableshim/hertospeakdespitethelimitednatureofthePrimaryLinguisticData(PLD,theinputsignalsreceived)andthedegeneratenature(frequentincorrectusage,utterancesofpartialsentences)ofthatdata.Giventhispovertyofthestimulus,alanguageacquisitionmodelrequiresanumberofcomponents.Firstly,thechildmusthaveatechniqueforrepresentinginputsignalsand,secondly,awayofrepresentingstructuralinformationaboutthem.Thirdly,theremustbesomeinitialdelimitationoftheclassofpossiblelanguagestructurehypotheses.Fourthly,thechildrequiresamethodfordeterminingwhateachofthesehypothesesimplieswithrespecttoeachsentence.Finally,anadditionalmethodisneededbywhichthechildcanselectwhichhypothesisiscompatiblewiththePLD.Equippedwiththisendowment,firstlanguagelearningisexplainedasperformedbyaLanguageAcquisitionDeviceprogressingthroughthefollowingstages:ThedevicesearchestheclassoflanguagestructurehypothesesandselectsthosecompatiblewithinputsignalsandstructuralinformationdrawnfromthePLD.Thedevicethenteststhecompatibilityusingtheknowledgeofimplicationsofeachhypothesisforthesentences.Onehypothesisor‘grammar’isselectedasbeingcompatiblewiththePLD.Thisgrammarprovidesthedevicewithamethodofinterpretingsentences(byvirtueofitscapacityforinternallyrepresentingstructuralinformationandapplyingthegrammartosentences).ThroughthisprocessthedeviceconstructsatheoryofthelanguageofwhichthePLDareasample.Chomskyarguesthatinthisway,thechildcomestoknowagreatdealmorethanshehas‘learned’,acquiringaknowledgeoflanguage,whichgoesfarbeyondthepresentedprimarylinguisticdataandisinnosensean'inductivegeneralization'fromthesedata.Insomeviewsoflanguageacquisition,theLADisthoughttobecomeunavailableafteracertainage—thecriticalperiodhypothesis(i.e.,issubjecttomaturationalconstraints).FeralchildrencasessuchasGenieprovidekeyexamplesfortheLADaspectofthenativisttheoryandthatitbecomesunavailableafteracertainage.TheLanguageAcquisitionDevice(LAD)isahypotheticalbrainmechanismthatNoamChomskypostulatedtoexplainhumanacquisitionofthesyntacticstructureoflanguage.Thismechanismendowschildrenwiththecapacitytoderivethesyntacticstructureandrulesoftheirnativelanguagerapidlyandaccuratelyfromtheimpoverishedinputprovidedbyadultlanguageusers.Thedeviceiscomprisedofafinitesetofdimensionsalongwhichlanguagesvary,whicharesetatdifferentlevelsfordifferentlanguagesonthebasisoflanguageexposure.TheLADreflectsChomsky'sunderlyingassumptionthatmanyaspectsoflanguageareuniversal(commontoalllanguagesandcultures)andconstrainedbyinnatecoreknowledgeaboutlanguagecalledUniversalGrammar.ThistheoreticalaccountofsyntaxacquisitioncontrastssharplywiththeviewsofB.F.Skinner,JeanPiaget,andothercognitiveandsocial-learningtheoristswhoemphasizetheroleofexperienceandgeneralknowledgeandabilitiesinlanguageacquisition.Seealso:LANGUAGEDEVELOPMENTBibliographyChomsky,Noam.AspectsoftheTheoryofSyntax.Cambridge,MA:MITPress,1965.LauraL.NamyReadmore:LanguageAcquisitionDevice-Chomsky,Languages,Syntax,Aspects,Lad,andSet