Intonation for infants The prosody of “motherese” Sameer ud Dowla Khan, Reed College Tuesday 14 May 2013
IntonationforinfantsTheprosodyof“motherese”
SameerudDowlaKhan,ReedCollegeTuesday14May2013
Outline
¡ QuestionsMotivationofstudy
¡ BackgroundIntonationalphonologyofEnglish,Bengali¡ DatacollectionExperiment,recordings,annotation
¡ ResultsIDSvs.non-IDS:similarities,differences¡ DiscussionProposedexplanationsforIDSdifferences
¡ ConclusionsSummary,upcomingextensions
Questions
Audience
¡ Wemakesubtlebutsystematicchangesinourspeechdependingonouraudience
¡ Someaudiencestriggerhyperarticulationl Non-nativespeakers1
1Knolletal.2006,Utheretal.2007
Audience
¡ Wemakesubtlebutsystematicchangesinourspeechdependingonouraudience
¡ Someaudiencestriggerhyperarticulationl Non-nativespeakers1
l Children/infants2
1Knolletal.2006,Utheretal.20072VideoofPatKuhl’sTEDtalk
Infant-directedspeech(IDS)
¡ Infant-directedspeech(IDS)ormothereseischaracterizedasinvolving:l Syntactically
¡ Shortersentenceswithsimplerstructure1¡ Focusmovement2
l Lexically¡ Smallervocabulary3¡ Paraphrasing3
1O’Grady1997:2502Cristia20113Ferguson1964,O’Grady1997:250
Infant-directedspeech(IDS)
¡ Infant-directedspeech(IDS)ormothereseischaracterizedasinvolving:l Phonetically
¡ Expansionofvowelspace(/i/vs./u/ vs./ɑ/)1¡ StopVOTmanipulation(/p t k/vs./b d ɡ/)2¡ Distinctiveprosody(intonation,rhythm)
1Andruski&Kuhl1996,Burnhametal.2002,Cristia20112Sundberg&Lacerda1999,Sundberg2001,butcf.Synnestvedt2010
Infant-directedspeech(IDS)
¡ IDSprosodyistraditionallyanalyzedfromanacoustic-phoneticapproach1
l Expansionofpitchrange
l Raisingofpitchmaximuml Exaggerationofcontours2
¡ Seenasanon-phonologicalorevenparalinguistic3phenomenon
1Jacobsonetal.1983,Sternetal.1983,Fernald&Simon1984,Fernaldetal.1989,Fernald&Mazzie1991,Greiser&Kuhl1998,Masataka19992Trueforbothtonalandnon-tonallgs.(Liuetal.2007)3Jacobsonetal.1983,O’Grady1997:250
Infant-directedspeech(IDS)
¡ Butintonationiscurrentlyseenasfullylinguisticandevenphonologicall Finiteinventoryoftonesl Hierarchicalprosodicstructurel Predictablevariationintones(allotones)l Grammaroftonalsequences(“tonotactics”)
¡ IsIDSintonationsomehowdifferent?
Infant-directedspeech(IDS)
Adult-directedspeech
Infant-directedspeech
Infant-directedspeech(IDS)
Infant-directedspeech
Adult-directedspeech
Basicquestions
1) Inadditiontothewiderpitchrange,aretherecategoricalchangesinIDSprosody?
2) Whatlinguisticinformationmightbeconveyedbysuchchanges?
3) Whatcouldbethepressuresmotivatingthesechanges?
Background
Intonationalphonology
¡ Tohelplookbeyondlg.-specificprosodicproperties,Ilookedattwolanguageswithtypologicallydivergentintonation:l MainstreamAmericanEnglish
l BangladeshiStandardBengali1
1ThevarietyillustratedinKhan2010
Intonationalphonology
¡ SharedfeaturesofEnglishandBengali:l Pitchaccents1:tonesonstressedsyllablesl Intonationphrases(IPs)2:largeprosodicunitsl Boundarytones:tonesmarkingendsofIPs
ThisisasomewhatidealizedpitchcontourH* H* H* H*
[ ]IP
L-L%
Intonationalphonology
¡ Language-specificfeatures:l Inventoryofintonationaltones
¡ EnglishhasnoHL%(highfallingboundary)¡ BengalihasnoH-L%(highplateauboundary)
l Meaningsconveyedbyspecifictonesequences¡ H*isdefaultinEnglish,sarcasticinBengali¡ L*isdefaultinBengali,doubtinginEnglish
English:pitchaccents
¡ English:inventoryof5basicpitchaccentsl Partialinventory:
Default Non-default(rising)H*(high) L+H*(earlyrise)1
L*+H(laterise)
l Choiceisrelatedtoattitude2,focusstatus2,andtonalenvironment3
1ManyresearchersconsiderH*andL+H*tobevariantsofthesamepitchaccent.2Beckman&Hirschberg19903Dainora2002,2006
English:intonationphrases
¡ English:5boundarytonescanoccurattheendsofintonationphrases(IPs)l Partialinventory:
¡ L-L%(lowfall)¡ H-H%(highrise)
l Choiceisrelatedtosentencetype,speakerconfidence,finality1
1Beckman&Hirschberg1990
Bengali:pitchaccents
¡ Bengali:inventoryof6pitchaccentsl Partialinventory:
Default Non-default(f-marked)L*(low) fH*(extrahigh) L*+fH(risetoextrahigh)
l Choiceisrelatedtospeakerattitude1,focusstatus/type2,andtonalenvironment
1H*markssarcasmorsurprise,L*otherwise(Khan2008,2013toappear)2Thechoiceoff-markedtonelargelydependsonfocustype(Khan2008,2013toappear)
Bengali:boundarytones
¡ Bengali:inventoryof5boundarytonesL-initial H-initialL%(lowfall) H%(highrise)LH%(lowrise) HL%(highfall) HLH%(highfall-rise)
l Choiceisrelatedtosentencetype,informationstructure,finality1
1Khan2008,2013toappear
Bengali:boundarytones
¡ Bengali:inventoryof5boundarytonesL-initial H-initialL%(lowfall) H%(highrise)LH%(lowrise) HL%(highfall) HLH%(highfall-rise)
l Choiceisrelatedtosentencetype,informationstructure,finality1
Bothcanserveastopicalizers
1Khan2008,2013toappear
Bengali:boundarytones
¡ Bengali:inventoryof5boundarytonesL-initial H-initialL%(lowfall) H%(highrise)LH%(lowrise) HL%(highfall) HLH%(highfall-rise)
l Choiceisrelatedtosentencetype,informationstructure,finality1
Bothcanserveascontinuationrises
1Khan2008,2013toappear
Datacollection
Design:subjects
¡ 19subjectsl 9speakersofEnglish(5M,4F)l 10speakersofBengali(5M,5F)
¡ Allwereparentsofyoungchildren¡ AllresideintheLosAngelesarea
Design:materials
¡ Recordedreadingsofthe“NorthWindandSun”fablel SuitableforadultspeechandIDSl Similarsemantics/pragmaticsacrosslanguagesl Consistentsemantics,morphosyntax,segmentalphonologyacrossconditions
Design:conditions
¡ Twoconditionsl Defaultreading(non-IDS):“Readatacomfortablepace.”
l Simulatedinfant-directedreading(IDS):“Readasthoughyouspeakingtoaninfant.”
¡ Sametext,illustratedwithchildlikedrawings¡ Stuffedanimalsarrangedaroundspeaker
Experiment:annotation
¡ Englishannotationl Segmental:orthographyl Prosodic:tonelabelsfromMAE_ToBI1
¡ Bengaliannotationl Segmental:phonemicromanizationl Prosodic:tonelabelsfromB-ToBI2
1Beckmanetal.20052Khan2008,2013toappear
Analysis
¡ Acoustic-phoneticmeasurementsl Pitchrange
¡ Categorical/phonologicalmeasurementsl Inventoryoftonesl Numberofpitchaccentsl NumberofIPsl Numberofeachtypeofpitchaccentl Numberofeachtypeofboundarytone
Results
Previewofresults
¡ What’sthesameacrossconditions:1) Foreachlg.,IDSandnon-IDScanbothbe
analyzedusingthesameprosodicmodel
¡ Whatdiffersacrossconditions:2) IDShaswiderpitchrange(highermax)3) IDShasahigherproportionofcertaintones4) IDShasmoreIPs5) IDShasmoreoverallcontourcomplexity
expected
we’llcomebacktothisinthediscussion
1)Structurepreservation
¡ IDSprosodyusesthesametonalinventoryandgrammarasnon-IDSprosodyl NoIDS-specifictonesorallotonesl NoIDS-specific“tonotactic”rulesl NoIDS-specificrelationsbetweentonesequencesandintonationalmeanings
1)Structurepreservation
¡ Intonationalstructurepreservationl cf.phonemicstructurepreservation,inwhichaphonologicalprocessresultsinasoundalreadyfoundinthephonemeinventory
l German/d/ à [–voi] / ___]word¡ /t/ alreadyfoundininventory
l Bengali/LH%/ à [HLH%] / [...___...]IDS (opt.)¡ /HLH%/alreadyfoundininventory
2)Pitchrange
¡ AllBengalispeakersraisedthef0maxinIDS
¡ f0minnotconsistentlylowered
¡ SamepatternseeninEnglish
¡ Followsfrompreviousstudies
¡ “Authentic”IDS
IDS non-IDS
meanf090%f0range
10%f0range
PreviewofEnglish-specificresults
¡ EnglishIDSinvolves:l Increaseinrisingpitchaccentsl IncreaseinIPs
3)English:pitchaccents
¡ Onaverage,speakersincreasedthenumberandproportionofrisingpitchaccentsinIDSl 3.9%increaseinL*+Hproportion[p=0.02]l 7.5%increaseinL+H*proportion[p=0.01]
byspkr.
4)English:intonationphrases
¡ Onaverage,Englishspeakersproduced33.3%(=3.44)moreIPsinIDS[p<0.01]
byspkr.
4)English:intonationphrases
L-H% L-L% L-L%
L-L%
] ] ]
]
AndsotheNWwasobligedtoconfessthattheSunwasthestrongerofthetwo
AndsotheNWwasobligedtoconfessthattheSunwasthestrongerofthetwo
L-L%
]
PreviewofBengali-specificresults
¡ BengaliIDSinvolves:l Increaseinf-markedpitchaccentsl IncreaseinIPsl IncreaseinHL%andHLH%boundarytones
3)Bengali:pitchaccents
¡ f-markedpitchaccentuseishigherinIDSforallbutonespeakerl fH*l L*+fH
3)Bengali:pitchaccents
fH*
thatmuchtravelertheirshawlheldtightly(IDS)
thatmuchtravelerhis/hershawlheldtightly(non-IDS)
L*
byspkr.
fH*,L*+fHinnon-IDS
fH*,L*+fHinIDS
4)Bengali:intonationphrases
¡ Onaverage,Bengalispeakersproduced49.0%(=8.97)moreIPsinIDS[p<0.01]
byspkr.
4)Bengali:intonationphrases
LH% H% L%
L%
] ] ]
]Atthatmomentatravelerwearingaheavyshawlcamewalkingtowardsthem
Atthatmomentatravelerwearingaheavyshawlcamewalkingtowardsthem
3)Bengali:boundarytones
¡ TheincreaseinIPscanbelargelyattributedtoincreasesinthoseendingin:l HL%(highfalling)l HLH%(highfalling-rising)
byspkr.
HL%,HLH%inIDS
HL%,HLH%innon-IDS
3)Bengali:boundarytones
Hainnon-IDSDefault
HLH%inIDSContinuation
HL%inIDSTopicalization
Summaryofresults
¡ TrueforIDSinbothlanguages:l Morenon-defaultpitchaccents
¡ RisingpitchaccentsinEnglish,f-markedinBengali¡ Despitelackofincreaseindefaultpitchaccents
l MoreIPs¡ Certainboundarytonesweremorecommon
¡ So,whydoweseethesemodifications?
Discussion
Why:pitchaccentpatterns
¡ WhydoesIDSinvolveanincreaseinnon-defaultaccents?l EnglishrisingL*+HandL+H*l Bengalif-markedfH*andL*+fH
¡ Thesetonescanmarkfocusedelements1
èGreateruseoffocusprosodyinIDS2
1Pierrehumbert&Hirschberg(1990)forEnglish,Khan(2008,2013)forBengali2IDSalsoinvolvesgreateruseoffocusmovementinthesyntax(Fernald&Mazzie1991).
Why:phrasingpatterns
¡ WhydoesIDSinvolvemoreIPs?l IPbreakshelpdisambiguatesyntaxl Boundarytonesconveyinformationstructure
¡ BengaliHL%canmarktopicalization
èMoremarkingofsyntactic/informationstructureinIDS
Why:contourpreference
¡ TherecouldbeotherreasonswhyrisingpitchaccentsandH-initialboundarytonesaremorecommoninIDSl Preferenceformorepitchvariation,to“keepthingsinteresting”fortheinfant1
l PreferencefortonesinvolvingHasinfantspreferhigherpitch2
1Fernald1991,Werker&McLeod19892Kearsley1973,Fernald&Kuhl1981
Why:contourpreference
¡ Butonlytoneswithwell-formedcomplexandhighcounterpartscanundergothissubstitution
¡ IDSbalancesgrabbing/keepinginfant’sattentionwithstructurepreservation
Conclusions
Returningtothequestions
¡ Aretherecategoricalchangesbetweennon-IDSandIDSprosody?l Moresubstitutionofdefaultpitchaccentswithnon-defaultpitchaccents
l HigherlikelihoodtoaddIPbreaksl Moresubstitutionoflower/simplertoneswithhigher/morecomplextones
l But...thebasicprosodicsystemisthesame
Yes(but...)
Returningtothequestions
¡ Whatlinguisticinformationmightbeconveyedbythechanges?l GreateruseofIPbreakscandisambiguatesyntacticstructure
l Greateruseofcertainboundarytonesandnon-defaultpitchaccentscanhighlighttopic,focus
Returningtothequestions
¡ Whatcouldbethepressuresmotivatingthesechanges?l Desiretoattractinfant’sattentionl Desiretoclarifycomplexstructuresl Intonationalstructurepreservation
Pressurespromotingtonalcomplexity
Pressurefightingtonalcomplexity
Workinprogress
¡ Moredataontheway!l SecondtranscribercurrentlyannotatingEnglishl SecondtranscriberhasalreadyannotatedBengali,dataiscurrentlybeinganalyzed
Workinprogress
¡ Moreprincipledwayoflookingattheconnectionbetweenphonologicalchangesandsyntax/informationstructurel e.g.isprobabilityofIPbreakhigheratlargesyntacticphrasebreaks?
¡ Agreatareaforcollaborationacrosslinguisticsubfields!
Thankyou!
SpecialthankstomycollaboratorKristineM.Yu,aswellastoJaimePannaRoemer,MeghaSundara,theexperimentalsubjects,andtheaudiencehere!