TwoMajorAreasoftheHumanBrainLanguageisrepresentedprimarilyinthelefthalfofthebrainwithinanareaaroundthesylvianfissure(acleavageseparatinglobesinthebrain-大脑侧裂)Languageactivityisnotlocalized,butcorelinguisticprocessesaretypicallyinthelefthemisphere.Specializationofthetwohalvesofthebrainisknownaslateralization,andispresenttosomeextentininfancy.Thereisincreasedspecializationasthebrainmaturesandhaslessplasticity（可塑性）.[note]:plasticity:AccordingtoLenneberg,beforetheendofthecriticalperiod,bothhemispheresareinvolvedtosomeextentinlanguageandonecantakeoveriftheotherisdamaged.Thisneurologicalflexibilityiscalledbrainplasticity.CriticalPeriodHypothesis(关键期假说)——LennebergPrincipalCommunicativeSpecializationofLandRHemisphereNotes:Hemisphericspecializationforlanguageisthesameregardlessofwhetherthelanguageisspokenornot.Thetypicaldistributionofprimaryfunctionsisprobablyduetothelefthemisphere’sbeingmorepowerfulthantherightandthereforebettersuitedforprocessingthehighlycomplexelementsoflanguage.HowIstheBrainOrganizedforMultipleLanguages?a>therelationbetweenbraindamageandthelossoflanguageb>differentlanguages'stimulic>usingelectricalstimulationatprecisepointsduringthesurgeryd>PositionEmissionTomography(正电子发射X射线层析照相术)SpecificQuestions1.Howindependentarethelanguagesofmultilingualspeakers?Nosingleanswertothisquestion(individualvariation&complexfactors)Conclusion:multiplelanguagesystemsareneithercompletelyseparatenorcompletelyfused.ErvinandOsgoodsuggestedathree-waypossibilityforhowlanguagesrelateinone’smind.Coordinate:parallellinguisticsystemsindependentofoneanother;Compound:afusedorunifiedsystem(simultaneousbilingualism);Subordinate:onelinguisticsystemaccessedthroughanother.2.Howaremultiplelanguagestructuresorganizedinrelationtooneanotherinthebrain?Arebothlanguagesstoredinthesameareas?Formostmultilinguals,L1andL2arestoredindifferentareasofthebrain,bothpredominantlyinareasofthelefthemisphere.ButrighthemispheremaybemoreinvolvedinL2thanL1.3.DoestheorganizationofthebrainforL2