the prosody of motherese - reed college · the prosody of “motherese” ... 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!