2.4.1　Definition of Incidental Vocabulary Acquisition

2.4.1DefinitionofIncidentalVocabularyAcquisition

ItisgenerallyacceptedthataconsiderablepercentageoftheL2vocabularyisacquiredincidentally,i.e.asa「by-product」ofreading(Nagy,Anderson,&Hermann,1985;Nation&Coady,1988;Nation,2001).Incidentalvocabularyacquisitionhasbeenidentifiedwitheitheracquisition(Krashen,1981)orimplicitlearning(Ellis,2008).Intheliterature,incidentalvocabularyacquisitionhasbeendefinedas「learningwithoutanintenttolearn,orasthelearningofonething,forexamplevocabulary,whenthestudent'sprimaryobjectiveistodosomethingelse」(Laufer&Hulstijn,2001,p.10),and「thelearningofnewwordsasaby-productofameaning-focusedcommunicativeactivity,suchasreading,listening,andinteraction,whichoccursthroughmultipleexposuretoawordindifferentcontexts」(Huckin&Coady,1999,p.185).ThisstudyusesthedefinitionofincidentalvocabularyacquisitiongivenbyEllis(2008),i.e.,「learningofsomespecificfeaturethattakesplacewithoutanyconsciousintentiontolearnit」(p.966).

Itisnotdifficulttolistouttheadvantagesofincidentalvocabularyacquisitionoverdirectinstruction:(a)itispedagogicallyefficientbecauseitallowstwoactivities,suchasvocabularyacquisitionandreading/listening,tooccuratthesametime,(b)itismoreindividualizedandlearner-basedbecausethevocabularybeingacquiredisdependentonthelearner'sownselectionoflearningmaterials,and(c)becauseincidentalvocabularyacquisitionusuallyoccursintheprocessofreading,vocabularyiscontextualized,whichgivesthelearnerarichersenseoftheword'suseandmeaningthanthatfromtraditionalexercises.

However,asforanexactdefinitionandcharacterizationoftheprocessesandmechanismsinvolvedinincidentalvocabularyacquisition,manyquestionsremainunanswered.Averygeneralproblemwiththeoperationaldefinitionofincidentalvocabularyacquisitiongivenaboveisthatitseemstosuggestthatincidentallearningoccursunconsciously.AsGass(1999)noted,however,definingincidentalvocabularyacquisitionasthe「side-effect」ofanotheractivityneglectstheactiveroleofthelearnerinthisprocess.Thefactthatlearningoccursasaby-productofreadingdoesnotautomaticallyimplythatitdoesnotinvolveanyconsciousprocesses.Theseemingequationof「incidental」with「unconscious」isalsocriticizedbyEllis(1994a,p.38),whobelievedthatincidentalvocabularyacquisitionisnon-explicitinsofarasitdoesnotinvolveanexplicitlearningintention(theoverallgoalofthelearneristextcomprehension),butthatneithertheprocessnortheproductofsuchlearningisnecessarilyimplicitinthesenseofnon-conscious.

Intypicalexperimentsinvestigatingincidentalvocabularylearning,learnersarerequiredtoperformataskinvolvingtheprocessingofsomeinformationwithoutbeingtoldthattheywillbeafterwardstestedontheirrecallofthatinformation.Onemethodistoexposelearnerstotherelevantmaterialwithoutaninstructiontolearn,whichgenerallymeansthatlearnersmustperformsometaskthatleadsthemtoexperiencetheto-be-testedmaterialbutdoesnotleadthemtoexpectalaterretentiontest.Forexample,learnersarerequiredtocompletealisteningtaskwithsomevocabularyitemsembeddedinthelisteningtext,andarelatertestedontherecallofthevocabularyitems,asinthestudyreportedinthisthesis.

Anotherwayofinvestigatingincidentallearningistoasklearnerstolearnsomething,butnottheinformationtargetedforsubsequenttesting.Forexample,learnersaretoldtolistentoatextandthenrecallthecontentsofit.However,theyarenottoldinadvancethattheywillbetestedafterwardsontheirrecalloftheunfamiliarwordsinthelisteningtext.