Ling 151/Psych 156A: Acquisition of Language...

Ling151/Psych156A:AcquisitionofLanguageII

Lecture6SoundsIII

Announcements

BeworkingonHW2(due1/26/18)

Beworkingonthesounds&soundsofwordsreviewquestions

Learningsounds

Moreaboutcontrastivesounds

Thereareanumberofacousticallysalientfeaturesforsounds.Allittakesforsoundstobecontrastiveisforthemtohave“opposite”valuesforonefeature.


Example:Englishsounds“k”and“g”differonlywithrespecttovoicing(VOT).They’reprettymuchidenticalonallotherfeatures.ManycontrastivesoundsinEnglishusethevoicingfeatureastherelevantfeatureofcontrast(p/b,t/d,s/z,etc.).However,thereareotherfeaturesthatareusedaswell(airflow,mannerofarticulation,etc.).


Taskforthechild:Figureoutwhichfeaturesareusedcontrastivelybythelanguage.Contrastivesoundsforthelanguagewillusuallyvarywithrespecttooneofthosefeatures.

voicing

p/b,t/d,s/z

Experimentalstudy:Dietrich,Swingley&Werker2007

DutchandEnglishcontrastivefeaturesdiffer.

InEnglish,thelength(duration)ofthevowelisnotcontrastive “cat”=“caat”

InDutch,thelength(duration)ofthevoweliscontrastive

“cat”≠ “caat”

(Japanesealsousesthisfeature)

Testingchildren’sperceptionofcontrastivesounds

Doesthedatadistributionshowthis?DutchandEnglishvowelsoundsinthenativelanguageenvironmentalsoseemtodiffer

“…studiessuggestthatdifferencesbetweenthelongandshortvowelsofDutcharelargerthananyanalogousdifferencesforEnglish.”–Dietrichetal.2007

DutchFrequencyofsoundininput

Vowelduration0

English

whatthesounddistributionsmaylooklike

short longshort long



Vowelduration0

English

Dutchvowellengthusedcontrastively;vowelstendtobeeitherveryshortorverylong

short long



Vowelduration0

English

Englishvowellengthnotusedcontrastively;vowelstendtobelessshortandlesslong(comparatively)

short long



Vowelduration0

English

Dutch=bimodaldistribution?



Vowelduration0

English

English=unimodaldistribution?

Learningfromrealdatadistributions

Howdoweknowthatchildrenaresensitivetodistributionalinformationlikethis?

Maye,Werker,&Gerken2002

Createdsyntheticsoundsrangingfrom[da]to[ta]thatwerenon-nativefortheinfants(becausetheywereunaspirated–withoutthelittlepuffofairafterthem).


• Familiarized6-to8-month-oldinfantstooneoftwosets– BimodalSet:Soundsontheendsnear[da]and[ta].– UnimodalSet:Soundsinthemiddle.

• Testpreferencefor:– 3636…(Alternating)vs.3333…(Non-alternating)stimuli

==<<

3 6 3 6 … 3 3 3 3


==

InfantstrainedontheBimodaldatahadanoveltypreferencefornon-alternatingtrials.Theylearnedtoexpectalteration,andweresurprisedbynon-alteration.

3 6 3 6 … 3 3 3 3


<<

==

InfantstrainedontheUnimodaldatadidnotprefer/dispreferoneovertheother.Thedidnotseemtolearnanyexpectation.

3 6 3 6 … 3 3 3 3


<<

==

3 6 3 6 … 3 3 3 3


<<

Oneexplanation:Infantsexpectedallthesoundstobeinonecategorysotheywereallthe“same”,whetheritwasalternatingornon-alternatingtokens.

Maye,Weiss,&Aslin2008

CreatedsoundsderivedfromHindispeechsounds,rangingfrom[da]to[ta]andfrom[ga]to[ka],varyinginvoiceonsettime(VOT).Allofthesewerenon-nativesoundsforEnglishspeakers,since[da]and[ga]wereprevoiced(VOT~-50ms)and[ta]and[ka]wereunaspirated(withoutthelittlepuffofair).


Lookingtimeinms

<≈><

Thelookingtimesforthefinalhabituationtrialsindicatehowlonginfantswerewillingtolistentothe7mssound(token6)playedoverandoveragain.

12345678

6 6 6 6…


Lookingtimeinms

<≈><

Thelookingtimesforthechangetrialsindicatehowlonginfantswerewillingtolistentothe-50mssound(token3),aftertheyhadbeenlisteningtothe7mssound(token6). 12345678

6 6 6 6… 6 6 3…


Lookingtimeinms

<≈><

Ifinfantsareabletodiscriminatethetwosounds(token3andtoken6),theyshouldbeinterestedwhentheyperceivethesoundchange.Thismeansthelookingtimesinthechangetrialswouldbehigherthaninthefinalhabituationtrials.

12345678

6 6 6 6… 6 6 3…


Lookingtimeinms

<≈><

Infantstrainedonabimodaldistributiondidperceivethesoundcontrast.

12345678

6 6 6 6… 6 6 3…


Lookingtimeinms

<≈><

Infantstrainedonaunimodaldistributiondidnotperceivethesoundcontrast.

12345678

6 6 6 6… 6 6 3…

(Again,thismayhavebeenbecausetheyperceivedallsoundsasbelongingtothesamecategory.)


Lookingtimeinms

<≈><

Infantstrainedonnon-languagestimuli(usedasacontrol)wereveryuninterestedinthesoundchange–theydidnotdetectit.(They’remoreinterestedinthesounditself,sincetheyhadn’tyetdishabituated.)

12345678

6 6 6 6… 6 6 3…


Lookingtimeinms

<≈><

Infantstrainedonabimodaldistributionofonecontrast(ex:[da]vs.[ta])wereabletogeneralizetheVOTdistinctiontoasoundcontrasttheyhadnotheardbefore(ex:[ga]vs.[ka]).

Thatis,theyrecognizedvoicingasacontrastivefeature.

12345678

6 6 6 6… 6 6 3…


Theseresultssuggestveryyounginfantsarecapableofusingthedistributionalinformationavailableintheirinputtocategoricallyperceivesounds.

Thiscanbeperceptionofsoundsasbelongingtoasinglecategory[unimodaldistribution]ortotwocategories[bimodaldistribution].

12345678

BacktoDietrich,Swingley,&Werker2007“…studiessuggestthatdifferencesbetweenthelongandshortvowelsofDutcharelargerthananyanalogousdifferencesforEnglish.”–Dietrichetal.2007


Vowelduration0

English

Dutch=bimodaldistribution?English=unimodaldistribution?

BacktoDietrich,Swingley,&Werker2007

Predictionifchildrenaresensitivetothisdistribution

Dutchchildrenshouldinterpretvoweldurationasameaningfulcontrastbecausethedistributionismorebimodal

Implication:Changetovowelduration=newword



Englishchildrenshouldnotinterpretvoweldurationasameaningfulcontrastbecausethedistributionismoreunimodal

Implication:Changetovowelduration=samewordasbefore

Dutchchildren:Changetovowelduration=newword



Dutchchildren:Changetovowelduration=newword

Englishchildren:Changetovowelduration=samewordasbefore

Dietrich,Swingley,&Werker2007

Testswith18-month-oldchildrenwhoknowsomewords(andsohavefiguredoutthemeaningfulsoundsintheirlanguage)

“Switch”Procedure:measureslookingtime

Dutch English



…thisisatam…lookatthetam

Same:lookatthetam!

Switch:lookatthetaam!

Habituation

Test

Dutch English




Same:lookatthetam!


Habituation

Test

Shouldberelativelyexpected

Dutch English




Same:lookatthetam!


Habituation

Test

Expectedifthesearen’tcontrastive

Dutch English




Same:lookatthetam!


Habituation

Test

Unexpectedifthesearecontrastive

Dutch English

Dietrich,Swingley,&Werker2007Experiment1:TestingEnglishandDutchkidsonDutchvoweldurations

Same:lookatthetam!


Test

Frequencyofsoundininput

Vowelduration0Dutch English


Same:lookatthetam!


Test

5.04sec 9.23sec

difference

Dutch


Same:lookatthetam!


Test

difference

Dutch

English

6.66sec 7.15sec nodifference


Same:lookatthetam!


Test

difference

Dutch

English

nodifference

ItseemsliketheseDutchdurationdifferencesarecontrastivejustfortheDutchkids.

Dietrich,Swingley,&Werker2007Exp1:Dutchvoweldurations

Same:lookatthetam!


Test

difference

nodifference

Experiment2:TestingEnglishandDutchkidsonEnglishvoweldurations

Frequency

Vowelduration0


Same:lookatthetam!


Test

difference

nodifference


difference

Dutch

5.92sec 8.16sec


Same:lookatthetam!


Test

difference

nodifference


difference

Dutch

English

7.34sec 8.04secnodifference


Same:lookatthetam!


Test

difference

nodifference


difference

Dutch

English

nodifference

ItseemsliketheseEnglishdurationdifferencesarecontrastivejustfortheDutchkids(eventhoughthedifferencebetweenthemisless).


Same:lookatthetam!

Switch:lookatthetem!

Test

difference

nodifference

Experiment3:TestingEnglishandDutchkidsonvowelqualitycontrast(a/e)

Exp2:Englishvoweldurations

difference

nodifference

Frequency

Vowelduration0

(ThisisacontrolconditiontomakesureEnglishkidscandothetaskwhenthesoundiscontrastiveforthem)


Same:lookatthetam!


Test

difference

nodifference



difference

nodifferencedifference

Dutch

4.08sec 5.72sec


Same:lookatthetam!


Test

difference

nodifference



difference

nodifference

difference

Dutch

English

6.31sec 9.31sec difference


Same:lookatthetam!


difference

nodifference



difference

nodifference

difference

Dutch

English

difference

Phew—itlookslikeEnglishkidscaninfactdothetask.Theybehaveastheyshouldwhentheyperceiveacontrast.

Test


difference

nodifference


difference

nodifference

Exp3:Vowelquality

difference

difference

Implicationsofexperiments1,2,and3:DutchchildrenrecognizevoweldurationascontrastivefortheirlanguagewhileEnglishchildrendonot.

Thiscanonlybeduetothedataencounteredbyeachsetofchildrenintheirlanguage.

Dietrich,Swingley,&Werker2007Thiscanonlybeduetothedataencounteredbyeachsetofchildrenintheirlanguage.


Vowelduration0

English

Dutchchildrenhaveacategoryboundaryapproximatelyhere.Englishchildrendonot.

Dutch


Whatdriveschildrentolearnthisdistinction?


Vowelduration0

Itcan’tbethewordstheyknowintheirvocabulary—“childrenthatyoungdonotseemtoknowmanywordpairsthatcouldclearlyindicateadistinction”

Dutch




Vowelduration0

Dutch

“childrenbegintoinducephonologicalcategories‘bottom-up’,basedontheirdiscoveryofclustersofspeechsoundsinphoneticspace…”




Vowelduration0

Dutch

“AnecessaryconditionforsuchlearningtobethedrivingforcebehindDutchchildren’sphonologicalinterpretationinthepresentstudiesisthatlongandshortvowelsbemoreclearlyseparableinDutchthaninEnglish”




Vowelduration0

Dutch

“…preliminaryexaminationofthisproblemusingcorporaofDutchchild-directedspeechindicatedthatthesetoflongandshortinstancesformedlargelyoverlappingdistributions.”

TheactualdistributionofDutchsounds

Uhoh!

Adriaans&Swingley2012Onesolution:Motheresemayprovideexaggerateddistributionswhensoundsareemphasized(givenacousticfocus),whichcanhelpinfantsfigureoutthecontrastivesounds.

ThreevowelcategoriesforEnglishspeakers

Alearningmodeltrainedonallsoundsinmotherese

Alearningmodeltrainedon“acousticallyfocused”soundsinmotherese

Thisonelooksalotclosertotherightcategories.

Swingley2009

Anotherpotentialsourceofinformation:Keepsomecontextualinformationforeachvowelsound(whatworditcamefrom,ifitcomesfromafrequentword).

Feldmanetal.2009,2013Assumingthatsoundsarepartofwordscanbehelpful–thissuggeststhatlearningaboutsoundsandwordsatthesametimeiseasierthanlearningsoundsseparatelyandthenlearningwords.(Feldman,Griffiths,&Morgan2009,Feldman,Griffiths,Goldwater,&Morgan2013)

VowelcategoriesforEnglishspeakers

Vowelcategorieslearnedbyacomputationalmodelwhensoundsareassumedtobepartofwords

Thislooksprettyclose!

Antetomasoetal.2017

But…theactualdatachildrenfacearemessierthanthisparticularmodelofsimultaneoussound&wordlearningcancurrentlyhandle(Antetomaso,Miyazawa,Feldman,Elsner,Hitczenko,&Mazuka2017).

Englishvowelcategorysamplesinwordcontextsfromactualchild-directedspeech

Thislooksalotmessier

Englishvowelcategorysamplesinwordcontextsthatthemodellearnedsuccessfullyfrombefore

Feldmanetal.2013b

Experimentalevidencethatinfantsarehelpedbywordcontextwhenfiguringoutsoundsarecontrastive:8-month-oldsdobetteratdistinguishingsoundsthatareheardindifferentwordcontexts(Feldman,Myers,White,Griffiths,&Morgan2013).

Feldmanetal.2013bDistinguishingsoundsthatareheardindifferentwordcontexts

12345678ah…………………aw

“ah”/a/vs.“aw”/ç/Minimalpaircontext: gutah….gutawNon-minimalpaircontext: gutah…litaw

Non-alternatingtrial: 3..3..3…or6…6…6…Alternatingtrial: 1…8…1…8

Feldmanetal.2013bDistinguishingsoundsthatareheardindifferentwordcontexts

12345678

ah…………………aw

Infantswhoheardthesoundsinthesame“word”don’tnoticethesoundchange(soundsarenotcontrastive).

Infantswhoheardthesoundsindifferent“words”noticethesoundchange(soundsarecontrastive).Theyaresurprisedwhenthesoundsdon’talternate.

Non-alternatingtrial:3..3..3…or6…6…6…Alternatingtrial: 1…8…1…8

gutah….gutaw

gutah…litaw

Asadults,wecanlookatalanguageandfigureoutwhatthecontrastivesoundsarebylookingatwhatchangesaword’smeaning.Butchildrencan’tdothis-theyfigureoutthecontrastivesoundsbeforetheyfigureoutmanywordformsandwordmeanings.

Discoveringcontrastivesounds:What’sthepointofitagain?

Theideaisthatoncechildrendiscoverthemeaningfulsoundsintheirlanguage,theycanbegintofigureoutwhatthewordsare.

Ex:AnEnglishchildwillknowthat“cat”and“caat”arethesameword(andshouldhavethesamemeaning).

Recap:Sounds

Childrenneedtolearnwhatthephonemesoftheirlanguagearebylisteningtotheirnativelanguageinput,andphonemeswillbecontrastivewithrespecttoatleastonefeature(likedurationorvoicing).

Infantsseemabletousethestatisticaldistributionofsoundstohelptheminferwhichsoundsarecontrastive.

Itmaybehelpfulforchildrentokeeptrackofwheretheyhearparticularsounds(thatis,inwhichwords)inordertofigureoutthephonemesoftheirlanguage.

Questions?

Youshouldbeabletodoupthroughquestion3onHW2andupthroughquestion25onthesounds&soundsofwordsreviewquestions.

Ling 151/Psych 156A: Acquisition of Language...

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