Effects of contextual support on preschoolers’ accented speech comprehension

25 Pages·2016·1.24 MB·English

by  Sarah C. Creel

JournalofExperimentalChildPsychology146(2016)156–180
ContentslistsavailableatScienceDirect
Journal of Experimental Child
Psychology
journal homepage: www.elsevier.com/locate/jecp
Effects of contextual support on preschoolers’
accented speech comprehension
Sarah C. Creela,⇑, Dolly P. Rojob, Angelica Nicolle Paulladaa
aUniversityofCalifornia,SanDiego,LaJolla,CA92093,USA
bUniversityofTexasatAustin,Austin,TX78712,USA
a r t i c l e i n f o a b s t r a c t
Articlehistory: Young children often hear speech in unfamiliar accents, but
Received24November2015 relativelylittleresearchcharacterizestheircomprehensioncapac-
Revised29January2016 ity. The current study tested preschoolers’ comprehension of
Availableonline4March2016
familiar-accentedversusunfamiliar-accentedspeechwithvarying
levelsofcontextualsupportfromsentenceframes(fullsentences
Keywords:
vs.isolatedwords)andfromvisualcontext(foursalientpictured
Accent
alternativesvs.theabsenceofsalientvisualreferents).Thefamiliar
Accentedspeech
Speechcomprehension accent advantage was more robust when visual context was
Wordrecognition absent,suggestingthatpreviousfindingsofgoodaccentcompre-
Adverselisteningconditions hension in infants and young children may result from ceiling
Eyetracking effects in easier tasks (e.g., picture fixation, picture selection)
relativetothemoredifficulttasksoftenusedwitholderchildren
andadults.Incontrasttopriorworkonmispronunciations,where
mosterrors were novelobject responses, children inthe current
study did not select novel object referents above chance levels.
Thissuggeststhatsomepropertyofaccentedspeechmaydissuade
childrenfrominferringthatanunrecognizedfamiliar-but-accented
word has a novel referent. Finally, children showed detectable
accentprocessingdifficultydespitepresumedincidentalcommu-
nityexposure.Resultssuggestthatpreschoolers’accentedspeech
comprehension is still developing, consistent with theories of
protracteddevelopmentofspeechprocessing.
(cid:1)2016ElsevierInc.Allrightsreserved.
⇑
Correspondingauthor.
E-mailaddress:[email protected](S.C.Creel).
http://dx.doi.org/10.1016/j.jecp.2016.01.018
0022-0965/(cid:1)2016ElsevierInc.Allrightsreserved.
S.C.Creeletal./JournalofExperimentalChildPsychology146(2016)156–180 157
Introduction
Withincreasingglobalization,listenersoftenencounterspeechinregionalorforeignaccentsdif-
ferentfromtheirown.Theselistenersincludeyoungchildren.Althoughthereisawealthofresearch
on the effects of unfamiliar accents on speech comprehension in adults, much less is known about
young children’s accented speech comprehension, as observed by Cristià et al. (2012) in a recent
reviewarticle.Thisisasignificantgapinknowledgegiventhataccentedspeechprovidesachallenge
to young children’s developing abilities in speech perception and word recognition (Bent, 2014;
Nathan,Wells,&Donlan,1998).Moreimportant,asCristiàetal.(2012)alsonoted,itpreventsthefield
from having a full developmental picture of accented speech comprehension from infancy through
childhoodthroughyoungandolderadulthood.Thecurrentstudyisanattempttodecreasethisgap.
Littleresearchcharacterizesaccentedspeechcomprehensioninyoungchildren(with,asdiscussed
shortly,afewexceptions),andexistingfindingsarespreadacrossparadigmsanddonotalwayspro-
duce identical conclusions. Therefore, it is not clear how well children comprehend unfamiliar-
accentedspeakers who theyencounter in everyday environmentsor what situationscreate greater
orlessereaseincomprehension.Thecurrentstudysoughttocharacterizeaccentedspeechprocessing
inpreschool-aged(3-to5-year-old)children.Inparticular,weaimedtoassesstheroleofdifferent
typesofcontextualsupport—sententialsemanticcontextandvisualscenecontext—andthepossibility
thatchildrenwillmisidentifyaccentedfamiliarwordsasnovelwords.
Accentedspeechmaybemorechallengingforchildreninthattheyaregenerallymoresusceptible
thanadultstoadverselisteningconditionsinspeechcomprehension(e.g.,Fallon,Trehub,&Schneider,
2000,2002).Thus,perceptualdifficultiesintroducedbyspeechinunfamiliaraccentsmaybeespecially
challengingforchildren.Anadditionalreasonwhyaccentedspeechmaybeespeciallychallengingfor
childrenisthat,becausepreschool-agedchildrenarerapidlyacquiringvocabulary,theyneedtoiden-
tify potentially novel word forms. This means that if childrenare overly sensitive to pronunciation
deviationsfromfamiliarwords,theymaymisidentifyfamiliarbutaccentedwords(e.g.,‘‘peeg”/pig/
forpig/pɪg/)asnovelwords.Ontheotherhand,ifchildrenacceptlargevariationsinpronunciation,
theyriskfailuretodistinguishsimilarwords(e.g.,pick/pɪk/vs.peek/pik/).Thenextsectionreviews
whatisknownaboutaccentedspeechrecognitionininfants,youngchildren,andadults.
Accentedspeechprocessingduringdevelopment
Infants’andtoddlers’accentedspeechprocessing
Althoughwedonothavespaceforanexhaustivereview,itshouldbenotedthatmostdevelopmen-
talresearchonwordorwordformrecognitioninunfamiliaraccents,oraccent-likevariabilitysuchas
deliberate mispronunciations, has focused on children up to around 2years of age (accents: Best,
Tyler, Gooding, Orlando, & Quann, 2009; Mulak, Best, Tyler, Kitamura, & Irwin, 2013; Schmale,
Cristià, Seidl, & Johnson, 2010; Schmale & Seidl, 2009; van Heugten & Johnson, 2014, in press; van
Heugten, Krieger, & Johnson, 2015; mispronunciations: Swingley, 2003; Swingley & Aslin, 2000,
2002;White&Aslin,2011;White&Morgan,2008),withmuchlessresearchonolderchildren(with
theonlyexceptionsbeing,tothebestofourknowledge,thefollowing:accents:Bent,2014;Bent&
Atagi, 2015; Nathan et al., 1998; mispronunciations: Creel, 2012; Newton & Ridgway, in press).
Cristiàetal.(2012),inreviewingaccentprocessingstudiesinvariousagegroups,notedthatresearch
onchildren’saccentprocessing,comparedwiththatofinfants/toddlersandyoungadults,is‘‘lesswell-
documented”(p.7).(Notethatthereismoreresearchwitholderchildrenonrecognizingorrespond-
ingtothepresenceofaccents:Floccia,Butler,Girard,&Goslin,2009;Girard,Floccia,&Goslin,2008;
Kinzler & DeJesus, 2013; Kinzler, Dupoux, & Spelke, 2007; Kinzler, Shutts, DeJesus, & Spelke, 2009;
Wagner,Clopper,&Pate,2014).
Infants,bysomeaccounts,showgoodwordorwordformrecognitionafter12or13monthsoflife.
Schmaleetal.(2010)andSchmaleandSeidl(2009)testedinfants’recognitionoffamiliarizedword
forms and found that infants recognize words despite unfamiliar regional accents by 12 months
(Schmaleetal.,2010)andforeignaccentsby13.5months(Schmale&Seidl,2009).Thesewordform
recognitionstudiesfitwithSwingleyandAslin’s(2000,2002)findingsfromalooking-while-listening
paradigmthatchildrenaged15monthsandoldershowsomedegreeofrecognitionofnon-canonically
158 S.C.Creeletal./JournalofExperimentalChildPsychology146(2016)156–180
pronouncedwords(intheircasedeliberatelymispronouncedwords);whenhearing‘‘Lookatthetog!”
childreninSwingleyandAslin(2002)lookedmoreatapictureddogthanapicturedshoe—although
they looked at the dog even more when dog was correctly pronounced. This result suggests that
infantsareatleastpartlyawareofthesimilaritybetweencorrectlypronouncedandmispronounced
forms(see White& Morgan,2008, for furtherexploration). Withadaptation,infants mayrecognize
accented forms of familiar words; van Heugten and Johnson (2014) showed accented word form
recognition in 15-month-olds following exposure to an accented reading of a familiar book, and
WhiteandAslin(2011)foundthat19-month-oldswhowereexposedtoavowelshiftaccent(‘‘socks”
pronounced as ‘‘sacks”) visually fixated the correct pictures when hearing artificially accented ver-
sionsoffamiliarwordssuchas‘‘bottle”(pronouncedas‘‘battle”).By2yearsofageatthelatest,chil-
drencanrecognizefamiliarwordsinunfamiliaraccentswithoutexposuretotheaccent(25months
forCanadiantoddlershearingAustralian-accentedEnglish:vanHeugtenetal.,2015;19monthsfor
AustraliantoddlershearingJamaican-accentedEnglish:Mulaketal.,2013)andnewlylearnedwords
if theyhave brief exposure to the accent (Schmale,Cristia, & Seidl, 2012). By 2.5years,childrenno
longer need accent exposure for recognizing familiar words (van Heugten & Johnson, in press) or
newly learned words (Schmale, Hollich, & Seidl, 2011). Interestingly, children in van Heugten and
Johnson’s(inpress)studyweremoresuccessfulatrecognizingtheaccentedwords(i.e.,theyfixated
thenamedpicturemorerobustly)whenwordswereembeddedinfull-sentencecontexts,hintingthat
at least one sort of context—acoustic–phonetic sentential context—may facilitate accent
comprehension.
Finally,arecentstudybySchmale,Seidl,andCristia(2015)suggeststhattoddlerscanbeinducedto
recognizeaccentedtokensofnewlylearnedwordsbysimplyexposingthemtoawiderangeoftalkers
(or even pictures of talkers) in their own accent. In that study, 2-year-olds were exposed to four
American-accented talkers either reading passages or silently waving and gesturing. Then children
werepresentedwithanovellabelingeventinafamiliaraccent,followedbyatwo-alternativechoice
wherethesameobjectwaslabeledinanunfamiliaraccent.Inbothexposureconditions,childrengen-
eralized word recognition to the unfamiliar accent. This differed from previous findings (Schmale
etal.,2012),where2-year-oldswithoutexposuretotheunfamiliaraccentfailedtogeneralize.This
implies that very young children, given a minimal amount of speech variability (or even visually
impliedspeechvariability),appeartobroadentherangeofpronunciationstheywillacceptforaword.
Whetherthisbroadeningoverextendstoacceptingaccent-atypicalpronunciations,orconfusingpre-
viouslydistinctwords(e.g.,/pɪk/and/pik/),isasyetunknown.Takentogether,thesestudiesofinfants
andtoddlersimplythatveryyoungchildrenarewellontheirwaytocomprehendingspeechinunfa-
miliaraccents.
Accentedspeechprocessinginpreschoolandprimaryschoolchildren
Whereas the work reviewed above suggests excellent accented speech comprehension by 2 to
2.5years ofage,studies ofolderchildrenaremore equivocal. Becauseinfantresearchand research
onolderchildrentendtousesomewhatdifferentparadigms,itisdifficulttocompareresultsacross
ages(seeCreel&Quam,inpress,forfurtherdiscussion).Ontheonehand,preschool-aged(3-to5-
year-old) children hearing mispronounced words in their native language phonological system are
fairlyaccurateinselectingthematchingitemoutoffourpicturesinadisplay;Creel(2012)foundthat
whenchildrenhearda single-phonological-featuremispronunciation(‘‘fesh”/feʃ/forfish /fɪʃ/),they
selectedthetargetpicture(thefish)nearly90%ofthetimefromanarraycontainingpicturesofafish,
two other familiar objects, and a novel object. Even when mispronunciations were more egregious
(/fɑʃ/),theystillselectedthetargetpictureapproximately60%ofthetime.Thissuggeststhat,similar
to Swingley and Aslin’s (2000, 2002) findings with toddlers, children readily detect the similarity
betweenthemispronouncedversionandthewordrepresentation.Justasinterestingwaswhathap-
penedwhenchildreninCreel’s(2012)studydidnotselectthetargetpicture(keepinginmindthat
targetpictureselectionswerethepredominantresponseoverall);lookingonlyatthesenontargettri-
als,childrenchoseanovelobjectroughly70%ofthetime,muchhigherthanthechancerateof33%
(nontargetchoiceswere1novelpicturevs.2familiarpictures).Thislatterfindingimpliesthatwhen
childrendonotrecognizeamispronouncedwordasfamiliar,theyaremostlikelytoassumethatitisa
S.C.Creeletal./JournalofExperimentalChildPsychology146(2016)156–180 159
novelform(e.g.,Markman&Wachtel,1988;seealsoHalberda,2003).Thisraisesthepossibilitythat
unfamiliar-accentedwords,ifunrecognized,willbetreatedasnovelwords.
AlthoughCreel’s(2012)studysuggeststhat3-to5-year-oldscomprehendunfamiliarpronuncia-
tions fairly well, research with word or sentence repetition tasks, largely using real accents, paints
a different picture (Bent, 2014; Bent & Atagi, 2015; Nathan et al., 1998; Newton & Ridgway, in
press).Nathanetal.(1998)tested4-and7-year-oldBritishEnglishspeakers’abilitiestorepeatiso-
latedwordsspokeninafamiliaraccent(LondonEnglish)versusanunfamiliaraccent(GlasgowEng-
lish).Theyfoundthatbothgroupsperformedlesswellontheunfamiliaraccent(57%vs.88%forthe
familiar accent), with improvement from the 4-year-olds (43%) to the 7-year-olds (71%). More
recently,Bent(2014)extendedalineofresearchonaccentedspeechrecognitioninadultstoencom-
passyoung(4-to7-year-old)children.Familiar-accented(AmericanEnglish)orunfamiliar-accented
(Korean-accented English) words were presented at a +5dB signal-to-noise ratio with speech-
shapednoise.Bentfoundthatchildrenweremuchlessaccurateatrepeatingwordsthanadultsand
were far less accurate for foreign-accented words (44% accuracy) than native-accented words (80%
accuracy).NewtonandRidgway(inpress),usingasentencerepetitioninnoisetaskwith6-and7-
year-olds,foundmuchhighersignal-to-noisethresholdsforaccuraterepetitionofartificiallyaccented
speechthanfamiliar-accentedspeech.
Thus, in contrast to studies of infants and toddlers, studies of older children (with Creel, 2012,
being an exception) suggest that they still have greater difficulty than adults in comprehending
accented speech. These findings concur with other research suggesting that children are less adept
than adults at comprehending speech in ideal (Hazan & Barrett, 2000; Ohde & Haley, 1997) and
non-ideal(Fallonetal., 2000, 2002) listeningconditions.Findingsof non-adult-like accent compre-
hension in young children are also consistent with accounts of protracted perceptual development
(e.g.,Creel&Jimenez,2012;seealsoBent&Atagi,2015),whichpositthatfullyadult-likespokenlan-
guageprocessingrequiresmanyyearsofperceptuallearning.
Remainingquestions
Currentevidenceismixedwithregardtothecircumstanceswherechildrensucceedinrecognizing
accentedspeech.Onepotentialexplanationfordifferencesacrossagesandtasksisthattasksthatpro-
videmorecontextualsupportleadtobetterperformance.Forexample,hearinganaccentedwordand
selectingitsreferentfromasmallsetofpictures(Creel,2012;vanHeugtenetal.,2015)islikelymuch
easierthanrecognizinganaccentedwordintheabsenceofanyvisualcontext(e.g.,Bent,2014;Nathan
etal.,1998).Similarly,itislikelyeasiertorecognizeanaccentedwordsuchas‘‘cows”inthesentence
‘‘Thefarmermilkedthecows”thanwhenhearing‘‘cows”inalesspredictablesentencecontextoras
anacousticallyisolatedtoken(seevanHeugten&Johnson,inpress,forevidencethat28-month-olds
recognizeaccentedwordsbetterwhenprecededbyanaccentedsentencecontext).Thus,thecurrent
studyteststhecontextualsupporthypothesisthatcontext—here,semanticsentencecontextandvisual
scene context—helps children to comprehend accented speech, potentially explaining discrepant
resultsinthedevelopmentalliterature.
Asecondissueconcernsthetypesoferrorschildrenmakewhentheymisperceiveaccentedspeech.
DotheytendtothinktheintendedreferentisanovelobjectlikechildreninCreel’s(2012)mispronun-
ciationstudy?Iftheydonotmakenoveltyerrors,whyisthisthecase?Althoughlittleempiricalwork
existstosuggestanswerstothisquestion,onepossibilityisthatunfamiliar-accentedpronunciations
might not be sufficiently different from the familiar-accented pronunciations to trigger a novelty
response,suchthatwordsareslightlyhardertorecognize(leadingtoslightlymoreerrors)butalso
donotregisterasdistinctlydifferentfromanyknownwords.Thatis,theymayregisterthataccented
‘‘pig” is similar to /pɪg/, /pig/, and /pik/, but it is not a clear instance of the novel word form /pig/.
Another possibility is that children may be more likely to dismiss unfamiliar-accented speakers’
knowledgeofnovelobjectnames(e.g.,Corriveau,Kinzler,&Harris,2013),dissuadingthemfrommak-
ingnovelobjectselectionsforunrecognizedaccentedwords.
160 S.C.Creeletal./JournalofExperimentalChildPsychology146(2016)156–180
Thecurrentstudy
These questions were addressed using a recently developed set of sentences, the Sentences for
Studying Accent Understanding in Child Experiments (SAUCE). Sentences (described in more detail
in Experiment 1) were recorded by 10 talkers with accents familiar to monolingual English-
speakingchildreninourarea(CaliforniaaccentsinthesouthwesternUnitedStates)andby10talkers
withlessfamiliaraccents(MexicanSpanishaccents).
ThestimuliwererecordedandstudieswereruninSanDiegoCounty,California.SanDiegoCounty
hasaSpanish-speakingpopulationof25%(Ryan,2013),althoughonly11%(i.e.,(cid:1)40%ofthe25%)of
residents are estimated to speak English less than ‘‘very well” (County of San Diego, 2013); this
implies,amongotherthings,thepresenceofaforeignaccent.Presumably,someofthosewhospeak
English‘‘verywell”arefluentenoughtohavenoidentifiableaccent,buteventhe11%figuresuggests
thatmonolingualchildreninourareaarelikelytohavehadincidentalexposuretoMexicanSpanish
accents(seeFloccia,DelleLuche,Durrant,Butler,&Goslin,2012,andHoward,Carrazza,&Woodward,
2014,foreffectsofcommunityaccentorlanguageexposure),soifanythingaccentedspeechcompre-
hensiondifficultyshouldbeameliorated.Suchlimitedcommunityexposureiscommoninanumber
ofmajorcitiesorothercommunitieswithimmigrantpopulationsand,thus,representsanimportant
situationfor scientificinvestigation. Furthermore,Spanishiscurrentlythemostprevalentlanguage
besidesEnglishintheUnitedStates(Ryan,2013)and,thus,islikelythemostprevalentforeignaccent
(or,moreaccurately,groupofforeignaccents).
Fourexperimentstestedpreschool-agedchildren’scomprehensionofaccentedspeechwithvary-
ingdegreesofcontextualsupport.Thefirsttwoexperimentsusedpicturepointingaccuracyandvisual
worldeyetracking(Tanenhaus,Spivey-Knowlton,Eberhard,&Sedivy,1995;Trueswell,Sekerina,Hill,
&Logrip,1999)toevaluatechildren’scomprehensionofwordsinsentences(Experiment1)andwords
inisolation(Experiment2)whenthevisualscenelimitspossibilitiestoasmallsetofpicturedrefer-
ents. The next two experiments used children’s word repetition responses to gauge recognition of
words in sentences (Experiment 3) and words in isolation (Experiment 4) when there is no visual
scenepresenttoconstrainchildren’sinterpretations.
Experiment1
Thefirstexperimentassessedunfamiliar-accentedversusfamiliar-accentedtargetwordrecogni-
tioninthepresenceofbothsententialandvisualcontexts;wordsoccurredinfullsentences,andchil-
dren selected the named picture from a display containing only four pictures. The target words
childrenheard were selected from a larger set of recorded sentences, where the selection criterion
washightargetwordtranscriptionaccuracybyadultlisteners(see‘‘Stimuli”sectionbelow).Ifchil-
dren’s accent comprehension is aided by visual context, performance should be equally good (high
accuracyandrapidvisualfixations)forbothaccents.Iftheyareaidedbysentencesensicality,sensical
sentence performance should be good in both familiar and unfamiliar accents, with lower perfor-
mance(loweredaccuracyandslowervisualfixations)fornonsensicalsentencesinunfamiliarversus
familiaraccents.
Method
Participants
Monolingual English-speaking preschool-aged children (N=32, 16 female and 16 male,
M =4.61years,SD=0.69,range=3.09–5.88)fromlocalpreschoolandday-carefacilitiestookpart
age
in the study. In this and the experiments that follow, parents reported that their children received
noexposuretoanylanguagebesidesEnglishathome.
Stimuli
Stimuliwerefullsentencesendinginatargetword.Sentenceswereineitheranaccentfamiliarto
monolingual English-speaking children in the region (Californian English) or a less familiar accent
S.C.Creeletal./JournalofExperimentalChildPsychology146(2016)156–180 161
(MexicanSpanish-accentedEnglish).ThefullsetofSAUCEsentencescontains100sensical,100non-
sensical, and 100 nonword-containing sentences recorded by 20 speakers (half U.S.-accented, half
Spanish-accented;halffemale,halfmale).TargetwordsforSAUCEsentencesconsistedofnamesfor
colorpicturesthatpreschool-agedchildrenlabeledconsistently.Adultandchildclozenormingdeter-
mined that target words were highly probable completions of sensical sentences (e.g., ‘‘The farmer
milked the cows”). To create nonsensical sentences, target words were scrambled across sentence
stems(e.g.,‘‘Thefarmermilkedthenose”).Nonword-containingsentencesmatchednonsensicalsen-
tencesexceptthatacontentwordinthesentencehaditsonsetconsonantreplacedwithadifferent
onsetconsonant,makingthesentenceframeitselflesssensical.Thesesentenceswerenotusedhere.
Ofthe10talkersperaccentthatweoriginallyrecorded,6talkersperaccent(3maleand3femalein
eachaccent;totalof12)wereusedinthecurrentexperiment.Thisallowedgoodcounterbalancingof
talkers across participants and conditions. Mexican-accented speakers were older on average
(M=32.0 years, SD=13.6, range=20–55) than Californian-accented speakers (M=22.8 years,
SD=6.6,range=18–36),inpartbecausewehadtorecruitfromthegeneralcommunityinorderto
findspeakerswejudgedtobesufficientlyaccentedinEnglish.Mexican-accentedspeakershadbegun
learning English at age 11 years or older (M=16.2years, SD=6.9, range=11–30), whereas
Californian-accentedspeakershadalllearnedEnglishfrombirth.Multiplerecordingsweremadeof
each sentence for each talker so that we could screen out gross errors and disfluencies and select
the most artifact-free recording. The 6 Spanish-accented speakers had slower average speech rates
(measured by sentence duration) than the 6 California-accented speakers (2632±313 vs.
2234±204ms),t(10)=3.78,p=.004.
Adult speakers of American English (N=49)1 transcribed sentences and words excised from sen-
tences.Targetwordrecognitionaccuracywascalculatedforeachutterance,andforthecurrentexperi-
mentrecordingswerechosentohavehighadulttranscriptionaccuracy.Thelogicwasthatthiswould
provideastrongertestofchildren’ssusceptibilitytoaccentunfamiliarity;showingthatchildrenhave
difficulty in comprehending words that adults also have difficulty in comprehending would be less
striking.
Overall,adultlistenersweremoreaccurateintranscribingfamiliar-accentedtargetwords(94.6%,
SD=22.5)thanunfamiliar-accentedtargetwords(90.7%,SD=29.0),v2=27.64,p<.0001,consistent
with previous reports of adult difficulty in comprehending accented speech (e.g., Bradlow & Bent,
2008). Each accented word token used in Experiment 1 was transcribed correctly both in isolation
andinitsfull-sentencecontextbyatleast3of4or5adults(Table1).Toguardagainstthepossibility
thatadultshadlearnedoradaptedfromprevioushearingsoftheword(eachwordorsentencewas
heardfivetimesperparticipantfromdifferentspeakers),accuraciesforselectedsoundfileswerealso
calculatedontheirfirsthearing,showingaccuracythatwasstillhigh(Table1,lower).Althoughallof
theSpanish-accentedrecordingswereincludedintheadulttranscriptionstudy,weincludedonlya
subset((cid:1)20%)ofthefamiliar-accentedrecordingsasafamiliaraccentbaselinemeasureinorderto
maximizeparticipants’timewithaccentedrecordings.Therefore,transcriptionaccuracyisnotavail-
ableforfamiliar-accentedmaterials.
Sentences for the child study were 48 matched pairs with identical sentence stems (e.g., ‘‘The
farmermilkedthecows/nose”).Atotalof25wordsoccurredasbothasensicaltargetandanonsen-
sicaltarget,butneverforthesamechild.Childrenheardonlyoneversionofeachsentence(sensicalor
nonsensical),andheardagivenwordastargetonlyonce.Oftheoriginal10speakersofeachaccent,6
wereselectedforinclusionintheexperiment(3femaleand3maleineachgroup)foreaseofcoun-
terbalancingwith48trials.Importantly,thepossiblesensicaltargetdidnotappearasanoptionon
nonsensicalsentencetrials(e.g.,thecowspictureon‘‘milkedthecows”trialswasreplacedwithapic-
tureofanoseon‘‘milkedthenose”trials)andviceversa.Thismeansthattherewerenohighlyplau-
sibleluresamongthepicturesonnonsensicaltrials—justonenovelpictureandtwofamiliarpictures
withlabelsphonologicallyunrelatedtothetargetandsemanticallyunrelatedtothesentence.
1 Forexpediency,somelistenersatourlinguisticallydiverseuniversitywereearlyacquirersofAmericanEnglishratherthan
nativespeakers.Preliminaryanalysesindicatednogroupdifferences,soresultsarecollapsedacrossgroups.
162 S.C.Creeletal./JournalofExperimentalChildPsychology146(2016)156–180
Table1
Means (and standard deviations) of proportion correct transcriptions of experimental sentences by adult English-speaking
listeners.
Adulttranscription Sensicality Insentence Isolatedword
Allinstances Sensical 0.990(0.053) 0.910(0.138)
Nonsensical 0.956(0.089) 0.931(0.108)
Firstinstance Sensical 0.989(0.104) 0.882(0.325)
Nonsensical 0.906(0.293) 0.885(0.320)
Procedure
Childrenweretestedinaquietroomorareaintheirday-carefacilityorpreschool.Sentenceswere
playedoverchild-sizedKidzGearheadphones(http://www.gearforkidz.com).Picturesandsoundfiles
werepresentedonaMacMinirunningMatlabR2008ausingPsychtoolbox-3(Brainard,1997;Pelli,
1997) and the Eyelink Toolbox (Cornelissen, Peters, & Palmer, 2002). On each trial, four pictures
appeared:thetargetpicture,onenovelobjectpicture,andtwofamiliarobjectpicturesthatdidnot
overlapsubstantiallyinsoundormeaningwiththetargetword.After500ms,thesoundfilebegan
playing. Children were asked to point to the picture that the person was talking about. An experi-
menterrecordedchildren’spointingresponsesbyclickingthemouseontheindicatedpicture.When
necessary,theexperimenterpromptedchildrentopointortoclarifytheirpoints.Visualfixationswere
recorded by an Eyelink 1000 eye tracker (SR Research, Mississauga, Ontario, Canada) operating in
remotemode.
Eachchildheard48sentencesintotal,equallydistributedacrossfourconditions:sensical/familiar
accent, sensical/unfamiliar accent, nonsensical/familiar accent, and nonsensical/unfamiliar accent.
Acrosschildren,eachsentencewasheardequallyoftenineachofthefourconditions.Therewereeight
differentlistssothateachwordineachcondition(sensicalorsenseless)washeardfrom4different
talkers,2peraccent.Eachlistwaspresentedinafixedorder,whichwasrandomwiththeconstraint
thatnopicturethatwasatargetontrialncouldrecur(asanontarget)anyearlierthantrialn+5.This
was intended to prevent children from paying undue attention to distractor pictures as a result of
recentoccurrenceasatarget.
Children also completed the Peabody Picture Vocabulary Test–Fourth Edition (PPVT-IV; Dunn &
Dunn,2007).Thisallowedustoassesswhetherlanguageknowledgefacilitatedaccentedspeechcom-
prehension. In most cases, both PPVT scores and chronological age correlated with overall perfor-
mance.Forconciseness,wepresentvocabularysizefindingsfromallfourexperimentsinaseparate
sectionpriortotheGeneralDiscussion.
Results
Thereweresubstantialdifferencesinbothaccuracy(Fig.1)andvisualfixationmeasures(Fig.2)as
afunctionofsentencesensicality.However,thedatasuggestednoaccent-relateddifferencesinaccu-
racyorvisualfixationstotargets.
Pointingresponses
Data were analyzed in R (R Core Team, 2014) using the package lme4 Version 1.1-7 (Bates,
Maechler, Bolker, & Walker, 2015) with logistic mixed-effects models. Mixed-effects models have
the advantage of accounting for participant and item variability in a single statistic. Jaeger (2008)
arguedthatlogisticregressionismoreappropriatethantransformedoruntransformedaccuracydata
becauseaccuracyisfundamentallybinomiallydistributed.
Alogisticregressionmodelwascomputedwithtargetselectionasthebinarydependentvariable
andaccent(familiarorunfamiliar;withinparticipantsanditems)andsensicality(sensicalsentence
ornonsensicalsentence;withinparticipantsanditems)assum-codedpredictors.Thestartingmodel
always contained maximal random effects structure (i.e., participant and item [target word] inter-
cepts)andparticipantanditemslopesforboththemaineffectsandtheinteraction,asrecommended
S.C.Creeletal./JournalofExperimentalChildPsychology146(2016)156–180 163
Fig.1. Experiment1:Children’saccuracyinpointingtothetargetpicture.Throughoutallfigures,errorbarsarestandarderrors.
byBarr,Levy,Scheepers,andTily(2013).Inthecurrentexperiment,themodelwiththemaximalran-
domeffectsstructuredidnotconverge,socorrelationsbetweenrandomeffectsweredroppedfrom
themodelassuggestedbyBarrandcolleagues.Themodelwithoutrandomeffectscorrelationscon-
vergedsuccessfully.Throughoutthearticle,effectsarereportedviamodelcomparisonusingtheanova
functioninR.Thatis,foreachreportedsignificancestatistic,twomodelswerecompared;bothhadthe
samerandomeffectsstructure,butonemodelomittedthefixedfactorofinterest(e.g.,accent).Asig-
nificantdifferenceinvarianceaccountedforindicatesthatthisfactor(here,accent)improvesthefitof
themodel.
Overall,childrenweremoreaccurateforwordsheardinsensicalsentences(93.2%)thannonsensi-
cal sentences (86.5%), v2(1)=9.72, p=.002. However, there was no effect of accent (unfamiliar
accented,88.9%vs.familiaraccented,90.8%),v2=0.87,p=.35,norwasthereanAccent(cid:3)Sensicality
interaction(v2=0.00,p=.95).
Hereandinotherexperiments,weranmodelsincludingtrialhalf(firsthalfoftrialsorsecondhalf
oftrials)asanadditionalpredictortoassesswhetherchildrenadaptedtotheaccentacrossthecourse
of the experiment. Because no significant effects or interactions with trial half were found in any
experiments,wedonotdiscussthemfurther.
Noveltyerrors
Our second question was whether children would misrecognize familiar but accented words as
novelwordforms.Ifso,morethanonethirdof‘‘errors”(nontargetresponses)shouldbenovelpicture
selections.Ifachilddidnotchoosethetarget,therewerethreeremainingpossibilities,oneofwhich
wasthenovelobject.Thus,theproportionofnoveltyerrorspredictedbychanceis1/3((cid:1).33).Propor-
tionsoferrorsthatwerenovelerrorsshowedlittlevisibleevidenceofnoveltyresponding(Table2).To
verify this statistically, we computed a logistic mixed-effects regression, including only nontarget
responses,andweassessedtheprobabilitythatanerrorwasaselectionofthenovelpicture(1;other-
wise0).Toensurethattheintercepttermassesseddeviationfromchanceratherthandeviationfrom
.50,anoffset—thelogoddsof1/3—wasincludedinthemodelspecification.Inaddition,becauseofthe
relativelysparsenumberoferrors,whichprecludesinclusionoflargenumbersofpredictors,onlythe
randomslopesforaccentwereincludedtotesteffectsofaccentonnoveltyresponding(followingBarr
etal.,2013).Neithertheinterceptterm(v2=0.89,p=.34)northeeffectofaccent(v2=0.67,p=.41)
approachedsignificance.Thissuggeststhatnoveltyerrorswerenomorethanwouldbepredictedby
chanceeitheroverall(proportionnovel=.295)oronaccentedtrials(proportionnovel=.294).
Visualfixations
Lookswereanalyzedina1-s(1000-ms)timewindowrangingfrom200to1200ms.Thismorethan
encompasses the full duration of target words (accented: 498±120ms; familiar-accented:
164 S.C.Creeletal./JournalofExperimentalChildPsychology146(2016)156–180
Table2
Experiments1and2:Proportionsofnoveltyresponding(andstandarddeviations)andproportionsoferrortrialsthatwerenovelty
responses(chance=.333).
Experiment Unfamiliaraccent Familiaraccent
Sensical Senseless Sensical Senseless
1 Novel .021(.042) .044(.056) .016(.033) .039(.063)
Familiar .052(.112) .104(.120) .047(.070) .083(.112)
Proportion .286 .298 .250 .319
2 Novel .047(.056) .034(.047) .044(.073) .018(.041)
Familiar .078(.099) .083(.116) .060(.090) .034(.066)
Proportion .375 .289 .425 .350
476±103ms;asmallbutsignificantdifference,p<.05)andincludesa200-mspositiveshifttoallow
fortheamountoftime((cid:1)200ms)neededtoexecuteaspeech-signal-basedsaccade(Matin,Shao,&
Boff,1993;seealsoSalverda,Kleinschmidt,&Tanenhaus,2014).FollowingBarr(2008),linearregres-
sionmodelswerecomputedonempirical-logit-transformedtargetlooksbyparticipantsandbyitems,
with accent and sensicality as within-participant and within-item factors. Factors were mean-
centeredandsum-coded.Duetothesmallnumberofdatapointsforbothparticipantanditemanal-
yses,randomeffectscorrelationswereremoved,aswastherandomeffectoftheinteraction.Totest
interactionsignificance,thebasemodelandthemodelwithouttheinteractionwerecomputedwith
onlytheinterceptandinteractionrandomeffectterm(again,withoutrandomeffectscorrelations),as
recommendedbyBarretal.(2013).
Aneffectofsensicality(v2=27.40,p<.0001andv2=20.87,p<.0001)revealedmoretargetlooks
overallwhen targets wereembeddedin sensical sentences. However, therewas noeffect of accent
(v2=2.23,p=.14andv2=2.14,p=.14)andnointeraction(v2=0.12,p=.73andv2=0.05,p=.82).
Thus, mirroring the accuracy data, there does not appear to be a deficit in recognition speed for
accentedspeech.
Discussion
Children showed equivalently high comprehension accuracy for familiar-accented (Californian)
and less familiar-accented (Mexican Spanish) spoken words in sentence contexts. Our findings are
somewhatconsistentwiththehypothesisthataverysmallsetofresponsepossibilities(fourpictures)
facilitates comprehension so that the effects of accented speech on comprehension are eliminated.
However, the role of sentence context in accented speech comprehension was not supported;
althoughresponsesweremoreaccurateforsensicalsentencesoverall,thiseffectdidnotinteractwith
accent. Thus, at least for visual context, our findings are consistent with the contextual support
hypothesis. A second account of this finding, however, is that because the sentences were chosen
basedonhighadulttranscriptionaccuracy,theywerealreadyeasytocomprehendeitherbecausethey
wereamongtheleastaccentedinthesetofrecordingsorbecausetheiraccentcharacteristicswere
lessdeleterioustorecognition.
Todissociatethesetwoexplanations,thenextexperimenttestedcomprehensionoftargetwords
alonewiththepre-target-wordportionofeachsentenceremoved.Theseexplanationsproducediffer-
entpredictions:ifwordsareweaklyaccentedanddonotelicitcomprehensiondifficulty,childrenwill
againshownoeffectsofaccentfamiliarity.However,ifcomprehensionisbolsteredbysemanticcon-
text(orhindered,inthecaseofnonsensicalsentences),anaccentfamiliarityeffectwillappear.
We also found no tendency for children to think that unrecognized accented words were novel
words.Thisisperhapsnotsurprisinggiventhataccentedspeechcomprehensionwasnotdetectably
weakerthanunaccentedspeechcomprehension.Thus,inExperiment2,weagainassessedwhether
childrenshowednoveltyrespondingfortheunfamiliaraccent.
S.C.Creeletal./JournalofExperimentalChildPsychology146(2016)156–180 165
Fig.2. Experiment1:Lookstopictures.Top:Sensicalsentences.Bottom:Nonsensicalsentences.Fam.,familiaraccent;Unfam.,
unfamiliaraccent;Distr.,distractor.
Experiment2
Method
Participants
MonolingualEnglish-speakingchildren(N=32,16femaleand16male,M =4.72years,SD=0.63,
age
range=3.24–5.58)fromthesamepopulationasinExperiment1tookpart.
Stimuliandprocedure
ThesewereidenticaltoExperiment1exceptthatchildrenheardonlythetargetwordsinsteadof
fullsentences.
Results
Accuracy
AsinExperiment1,alogisticregressionmodelwascomputedwithtargetselectionasthebinary
dependent variable and with accent and sensicality as contrast-coded predictors. The maximal