a phonologically weak contrast can induce phone5c...

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A phonologically weak contrast can induce phone5c overlap Margaret E. L. Renwick 1 , Ioana Vasilescu 2 , Camille Dutrey 2 , Lori Lamel 2 , Bianca Vieru 2,3 1 The University of Georgia, USA, [email protected] 2 LIMSI/CNRS, France 3 Vocapia Research, France The Romanian vowel system is unique among the Romance languages, in par5cular for its phonemic central vowels and rare diphthongs (Chitoran 2002) Marginal contrast in Romanian (Renwick 2014) ² Central /ɨ, ʌ/ are historical allophones in near-complementary distribu5on ² /ɨ/: Typically (90%) found in pre-nasal, stressed contexts; never post-tonic [ˈkɨmp] ‘eld’ [ˈlɨna] ‘wool (def.)’ [ˈvɨna] ‘vein (def.)’ ² /ʌ/: Usually unstressed, word-final (46%); has a large morphological role [ˈkasʌ] ‘house’ [ˈsutʌ] ‘hundred’ [pʌˈtuts] ‘bed (dim.)’ ² Few minimal pairs exist [rɨw] ‘river’ [rʌw] ‘bad’ [vɨr] ‘I thrust’ [vʌr] ‘cousin’ [tsɨr j ] ‘sea mackerels’ [tsʌr j ] ‘lands (n.)’ ² Both /ɨ, ʌ/ have low type frequency, sugges5ng low func5onal load ² It was hypothesized that the phonologically weak contrast between /ɨ, ʌ/ was subject to phone5c merger; however, studies of produc5on and percep5on in laboratory speech found li‘le evidence for this. References Chitoran, I. (2002). The Phonology of Romanian: A Constraint-Based Approach. Berlin; New York: Mouton de Gruyter. Fougeron, C., & Audibert, N. (2011). Tes5ng various metrics for the descrip5on of vowel distor5on in dysarthria. In Proceedings of the 17th Interna>onal Congress of Phone>c Sciences (pp. 1–4). Hong Kong. Gendrot, C., & Adda-Decker, M. (2005). Impact of Dura5on on F1/F2 formant values of oral vowels: an automa5c analysis of large broadcast news corpora in French and German. In Proceedings of Eurospeech (pp. 2453–2456). Lisbon. Hall, K. C. (2013). A typology of intermediate phonological rela5onships. The Linguis>c Review, 30(2), 215–275. Hall, K. C., Allen, B., Fry, M., Mackie, S., & McAuliffe, M. (2015). Phonological CorpusTools, Version 1.1.0. [Computer program]. Retrieved from h‘ps://github.com/PhonologicalCorpusTools/CorpusTools/releases Hocke‘, C. F. (1966). The quan>fica>on of func>onal load: A linguis>c problem (Memorandum No. RM-5168-PR). Lobanov, B. M. (1971). Classifica5on of Russian vowels spoken by different speakers. The Journal of the Acous>cal Society of America, 49(2B), 606– 608. Mahalanobis, P. C. (1936). On the generalized distance in sta5s5cs. Proceedings of the Na>onal Ins>tute of Sciences (CalcuNa), 2, 49–55. Nadeu, M., & Renwick, M. E. L. (2016). Varia5on in the lexical distribu5on and implementa5on of phone5cally similar phonemes in Catalan. Journal of Phone>cs, 58, 22–47. h‘p://doi.org/10.1016/j.wocn.2016.05.003 Renwick, M. E. L. (2014). The Phone>cs and Phonology of Contrast: The Case of the Romanian Vowel System. Berlin, Boston: De Gruyter Mouton. Vasilescu, I., Vieru, B., & Lamel, L. (2014). Exploring Pronuncia5on Variants for Romanian Speech-to-Text Transcrip5ons. In Proceedings of SLTU. St. Petersburg, Russia. Wedel, A., Jackson, S., & Kaplan, A. (2013). Func5onal load and the lexicon: Evidence that syntac5c category and frequency rela5onships in minimal lemma pairs predict the loss of phoneme contrasts in language change. Language and Speech, 56(3), 395–417. Research Ques6on: How is the phonologically weak contrast between /ɨ, ʌ/ realized in con5nuous speech? Data and Methods Acous>cs of 7 monophthongs compared across laboratory vs. broadcast speech. Laboratory speech (Renwick 2014) ² Stressed and unstressed vowels; target words in a frame sentence with 3 repe55ons ² 18 na5ve speakers (3 male) ² Formant values (F1, F2) extracted at midpoint; hand-checked ² 5,261 tokens (2,396 central vowels) Broadcast speech (Vasilescu, Vieru & Lamel 2014) ² Mixture of prepared speech from news shows, and semi-spontaneous debates from TV channel Antena, in the standard Southern dialect ² 7 hours, 86 speakers (male & female; adult) ² Segment boundaries automa5cally aligned ² Formant values extracted at midpoint (Gendrot & Adda-Decker 2005) ² Acous5c filtering of data ² Tokens with voicing in < 40% of vowel were excluded ² Each token’s Mahalanobis distance (Mahalanobis 1936) was calculated rela5ve to a speaker- and vowel-specific centroid; tokens with high distance (based on a χ 2 distribu5on) were excluded as outliers ² Vowel tokens analyzed: 104,456 (11,006 central vowels) ² Vowels’ func5onal load calculated from 9,032 unique words (Hall et al. 2015) Normaliza5on and analysis ² Formant values normalized by speaker (Lobanov 1971) ² Acous5c overlap in standard devia5ons of F1 calculated among adjacent vowel pairs (Fougeron & Audibert 2011) Results: vowel frequency and func6onal load in broadcast speech ² [ɨ, ʌ] appear in many func5on words, but are rare, with complementary distribu5ons Discussion ² The contrast between [ɨ, ʌ] is severely diminished in con5nuous speech ² [ɨ] is lower (higher F1) in broadcast than in laboratory speech ² Greater central vowel overlap occurs in broadcast speech ² Centraliza5on is not a byproduct of reduc5on (via shortening) ² Func5onal load of the /ɨ, ʌ/ contrast is lowest of all vowel pairs ² Speakers’ cogni5ve representa5ons of /ɨ, ʌ/ may not be separable from context ² Merger is strongest pre-nasally, where /ɨ/ is strongly condi5oned ² Underlying vowel quality highly condi5oned by morphology and phonology ² Future perceptual studies will indicate listener sensi5vity to vowel quality, independent of phonological context Context [ɨ] [ʌ] CVC 30.5% [romɨˈnia] ‘Romania’ 26.6% [ˈastʌz j ] ‘today’ #VC 67.2% [ɨn] ‘in’ 0.4% [ˈʌsta] ‘this one’ CV# 0.0% Ø 65.8% [sʌ] ‘that (conj.)’ Other 2.3% [ˈmɨ̯ine] ‘tomorrow’ 7.2% [sʌw] ‘his’ Total 100% 100% Phonological contras6veness and its consequences ² Sounds separated by even one minimal pair are considered contras5ve phonemes. But what if their distribu5on is mostly predictable, and nearly complementary? Do speakers and listeners treat weak, marginal contrasts differently from others? ² Characteris5cs of marginal contrast Near or par5al predictability, phone5c variability, frequency imbalance, scarcity of minimal pairs, phone5c overlap (Hall 2013, Nadeu & Renwick 2016) ² Func5onal load How much neutraliza5on would result from the loss of a contrast? (Hocke‘ 1966) More minimal pairs = higher func5onal load ² Language change over 5me Contrasts with low func5onal load are more likely to merge (Wedel et al. 2013) /i/ /ɨ/ /u/ /e/ /ʌ/ /o/ /e̯a/ /a/ /o̯a/ Func6onal load, calculated via type frequency, using change in entropy algorithm [e] [i] [o] [u] [ɨ] [ʌ] [a] 0.0428 0.0143 0.0071 0.0135 0.0025 0.0456 [e] 0.0257 0.0032 0.0107 0.0011 0.0545 [i] 0.0018 0.0061 0.0007 0.0078 [o] 0.0025 0.0011 0.0018 [u] 0.0032 0.0036 [ɨ] 0.0004 22.6% 28% 18.2% 3.3% 9.8% 10.9% 7.2% 23.2% 28.7% 16.8% 3.3% 9.9% 10.8% 7.2% All data (N = 125,501) Filtered data (N = 104,456) 0 10000 20000 30000 0 10000 20000 30000 a e i o u a e i o u Vowel Token count Vowel frequency Results: acous6cs of lab speech vs. broadcast speech Lab Broadcast -100 0 ea ie oa uo a ea ie oa uo a Adjacent vowel pair Mean F1 overlap (Hz) pair ea ie oa uo a Lab Broadcast -1 0 1 -1 0 1 2 -1 0 1 2 Z-scored F2 Z-scored F1 vowel a e i o u Female speakers Lab Broadcast -1 0 1 -1 0 1 -1 0 1 Z-scored F2 Z-scored F1 vowel a e i o u Male speakers Lab Broadcast -100 0 ea ie oa uo a ea ie oa uo a Adjacent vowel pair Mean F1 overlap (Hz) pair ea ie oa uo a In broadcast speech, [ɨ] is heavily centralized The central vowels (and [u, o]) overlap in the F1 dimension, in broadcast speech Does [ɨ] centralize only in short tokens? No. Correla5on of Z(F1) with dura5on is not significant (p > 0.05). Fricative Liquid Nasal Stop -2 -1 0 1 2 -1 0 1 -1 0 1 -1 0 1 -1 0 1 Z-scored F2 Z-scored F1 vowel Following manner in broadcast speech Fricative Liquid Nasal Stop -2 -1 0 1 -2 -1 0 1 2 -2 -1 0 1 2 -2 -1 0 1 2 -2 -1 0 1 2 Z-scored F2 Z-scored F1 vowel Following manner in broadcast speech In broadcast speech, [ɨ] centralizes most in pre-nasal contexts Lab Broadcast -2 -1 0 1 2 0.1 0.2 0.3 0.4 0.1 0.2 0.3 0.4 Vowel Duration (sec) Vowel F1 (Z-scored) vowel Lab Broadcast -2 -1 0 1 2 0.1 0.2 0.3 0.4 0.5 0.1 0.2 0.3 0.4 0.5 Vowel Duration (sec) Vowel F1 (Z-scored) vowel

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Page 1: A phonologically weak contrast can induce phone5c overlapfaculty.franklin.uga.edu/mrenwick/sites/faculty... · A phonologically weak contrast can induce phone5c overlap Margaret E

Aphonologicallyweakcontrastcaninducephone5coverlap

MargaretE.L.Renwick1,IoanaVasilescu2,CamilleDutrey2,LoriLamel2,BiancaVieru2,3

1TheUniversityofGeorgia,USA,[email protected]/CNRS,France3VocapiaResearch,France

TheRomanianvowelsystemisuniqueamongtheRomancelanguages,inpar5cularforitsphonemiccentralvowelsandrarediphthongs(Chitoran2002)

MarginalcontrastinRomanian(Renwick2014)²  Central/ɨ,ʌ/arehistoricalallophonesinnear-complementarydistribu5on²  /ɨ/:Typically(90%)foundinpre-nasal,stressedcontexts;neverpost-tonic

[ˈkɨmp] ‘field’ [ˈlɨna] ‘wool (def.)’ [ˈvɨna] ‘vein (def.)’²  /ʌ/:Usuallyunstressed,word-final(46%);hasalargemorphologicalrole

[ˈkasʌ] ‘house’ [ˈsutʌ] ‘hundred’ [pʌˈtuts] ‘bed (dim.)’ ²  Fewminimalpairsexist

[rɨw] ‘river’ [rʌw] ‘bad’ [vɨr] ‘I thrust’ [vʌr] ‘cousin’ [tsɨrj] ‘sea mackerels’ [tsʌrj] ‘lands (n.)’

²  Both/ɨ,ʌ/havelowtypefrequency,sugges5nglowfunc5onalload²  Itwashypothesizedthatthephonologicallyweakcontrastbetween/ɨ,ʌ/

wassubjecttophone5cmerger;however,studiesofproduc5onandpercep5oninlaboratoryspeechfoundli`leevidenceforthis.

ReferencesChitoran,I.(2002).ThePhonologyofRomanian:AConstraint-BasedApproach.Berlin;NewYork:MoutondeGruyter.Fougeron,C.,&Audibert,N.(2011).Tes5ngvariousmetricsforthedescrip5onofvoweldistor5onindysarthria.InProceedingsofthe17th

Interna>onalCongressofPhone>cSciences(pp.1–4).HongKong.Gendrot,C.,&Adda-Decker,M.(2005).ImpactofDura5ononF1/F2formantvaluesoforalvowels:anautoma5canalysisoflargebroadcastnews

corporainFrenchandGerman.InProceedingsofEurospeech(pp.2453–2456).Lisbon.Hall,K.C.(2013).Atypologyofintermediatephonologicalrela5onships.TheLinguis>cReview,30(2),215–275.Hall,K.C.,Allen,B.,Fry,M.,Mackie,S.,&McAuliffe,M.(2015).PhonologicalCorpusTools,Version1.1.0.[Computerprogram].

Retrievedfromh`ps://github.com/PhonologicalCorpusTools/CorpusTools/releasesHocke`,C.F.(1966).Thequan>fica>onoffunc>onalload:Alinguis>cproblem(MemorandumNo.RM-5168-PR).Lobanov,B.M.(1971).Classifica5onofRussianvowelsspokenbydifferentspeakers.TheJournaloftheAcous>calSocietyofAmerica,49(2B),606–

608.

Mahalanobis,P.C.(1936).Onthegeneralizeddistanceinsta5s5cs.ProceedingsoftheNa>onalIns>tuteofSciences(CalcuNa),2,49–55.Nadeu,M.,&Renwick,M.E.L.(2016).Varia5oninthelexicaldistribu5onandimplementa5onofphone5callysimilarphonemesinCatalan.Journal

ofPhone>cs,58,22–47.h`p://doi.org/10.1016/j.wocn.2016.05.003Renwick,M.E.L.(2014).ThePhone>csandPhonologyofContrast:TheCaseoftheRomanianVowelSystem.Berlin,Boston:DeGruyterMouton.Vasilescu,I.,Vieru,B.,&Lamel,L.(2014).ExploringPronuncia5onVariantsforRomanianSpeech-to-TextTranscrip5ons.InProceedingsofSLTU.St.

Petersburg,Russia.Wedel,A.,Jackson,S.,&Kaplan,A.(2013).Func5onalloadandthelexicon:Evidencethatsyntac5ccategoryandfrequencyrela5onshipsin

minimallemmapairspredictthelossofphonemecontrastsinlanguagechange.LanguageandSpeech,56(3),395–417.

ResearchQues6on:Howisthephonologicallyweakcontrastbetween/ɨ,ʌ/realizedincon5nuousspeech?

DataandMethodsAcous>csof7monophthongscomparedacrosslaboratoryvs.broadcastspeech.Laboratoryspeech(Renwick2014)²  Stressedandunstressedvowels;targetwordsinaframesentencewith3repe55ons²  18na5vespeakers(3male)²  Formantvalues(F1,F2)extractedatmidpoint;hand-checked²  5,261tokens(2,396centralvowels)

Broadcastspeech(Vasilescu,Vieru&Lamel2014)²  Mixtureofpreparedspeechfromnewsshows,andsemi-spontaneousdebatesfrom

TVchannelAntena,inthestandardSoutherndialect²  7hours,86speakers(male&female;adult)²  Segmentboundariesautoma5callyaligned²  Formantvaluesextractedatmidpoint(Gendrot&Adda-Decker2005)²  Acous5cfilteringofdata

²  Tokenswithvoicingin<40%ofvowelwereexcluded²  Eachtoken’sMahalanobisdistance(Mahalanobis1936)wascalculatedrela5ve

toaspeaker-andvowel-specificcentroid;tokenswithhighdistance(basedonaχ2distribu5on)wereexcludedasoutliers

²  Voweltokensanalyzed:104,456(11,006centralvowels)²  Vowels’func5onalloadcalculatedfrom9,032uniquewords(Halletal.2015)

Normaliza5onandanalysis²  Formantvaluesnormalizedbyspeaker(Lobanov1971)²  Acous5coverlapinstandarddevia5onsofF1calculatedamongadjacentvowelpairs

(Fougeron&Audibert2011)

Results:vowelfrequencyandfunc6onalloadinbroadcastspeech²  [ɨ,ʌ]appearinmanyfunc5onwords,butarerare,withcomplementarydistribu5ons

Discussion² Thecontrastbetween[ɨ,ʌ]isseverelydiminishedincon5nuousspeech

²  [ɨ]islower(higherF1)inbroadcastthaninlaboratoryspeech² Greatercentralvoweloverlapoccursinbroadcastspeech² Centraliza5onisnotabyproductofreduc5on(viashortening)

² Func5onalloadofthe/ɨ,ʌ/contrastislowestofallvowelpairs

² Speakers’cogni5verepresenta5onsof/ɨ,ʌ/maynotbeseparablefromcontext² Mergerisstrongestpre-nasally,where/ɨ/isstronglycondi5oned² Underlyingvowelqualityhighlycondi5onedbymorphologyandphonology² Futureperceptualstudieswillindicatelistenersensi5vitytovowelquality,

independentofphonologicalcontext

Context [ɨ] [ʌ] CVC 30.5%[romɨˈnia] ‘Romania’ 26.6%[ˈastʌzj] ‘today’ #VC 67.2%[ɨn] ‘in’ 0.4%[ˈʌsta] ‘this one’ CV# 0.0%Ø 65.8%[sʌ] ‘that (conj.)’ Other 2.3%[ˈmɨ̯ine] ‘tomorrow’ 7.2%[sʌw] ‘his’ Total 100%   100%

Phonologicalcontras6venessanditsconsequences²  Soundsseparatedbyevenoneminimalpairareconsideredcontras5vephonemes.

Butwhatiftheirdistribu5onismostlypredictable,andnearlycomplementary?Dospeakersandlistenerstreatweak,marginalcontrastsdifferentlyfromothers?

²  Characteris5csofmarginalcontrastNearorpar5alpredictability,phone5cvariability,frequencyimbalance,scarcityofminimalpairs,phone5coverlap(Hall2013,Nadeu&Renwick2016)

²  Func5onalloadHowmuchneutraliza5onwouldresultfromthelossofacontrast?(Hocke`1966)Moreminimalpairs=higherfunc5onalload

²  Languagechangeover5meContrastswithlowfunc5onalloadaremorelikelytomerge(Wedeletal.2013)

/i/ /ɨ/ /u/

/e/ /ʌ/ /o/

/e̯a/ /a/ /o̯a/

Func6onalload,calculatedviatypefrequency,usingchangeinentropyalgorithm

[e] [i] [o] [u] [ɨ] [ʌ][a] 0.0428 0.0143 0.0071 0.0135 0.0025 0.0456

[e] 0.0257 0.0032 0.0107 0.0011 0.0545

[i] 0.0018 0.0061 0.0007 0.0078

[o] 0.0025 0.0011 0.0018

[u] 0.0032 0.0036

[ɨ] 0.0004

22.6%

28%

18.2%

3.3%

9.8%10.9%

7.2%

23.2%

28.7%

16.8%

3.3%

9.9%10.8%

7.2%

All data (N = 125,501)

Filtered data (N = 104,456)

0

10000

20000

30000

0

10000

20000

30000

a e i � o u �

a e i � o u �Vowel

Toke

n co

unt

Vowel frequency

Results:acous6csoflabspeechvs.broadcastspeech

Lab Broadcast

-100

0

ea ie �� oa uo �a ea ie �� oa uo �aAdjacent vowel pair

Mea

n F1

ove

rlap

(Hz)

paireaie��oauo�a

Lab Broadcast

-1

0

1

-1012 -1012Z-scored F2

Z-sc

ored

F1 vowel

aei�ou�

Female speakersLab Broadcast

-1

0

1

-101 -101Z-scored F2

Z-sc

ored

F1 vowel

aei�ou�

Male speakers

Lab Broadcast

-100

0

ea ie �� oa uo �a ea ie �� oa uo �aAdjacent vowel pair

Mea

n F1

ove

rlap

(Hz)

paireaie��oauo�a

Inbroadcastspeech,[ɨ]isheavilycentralized

Thecentralvowels(and[u,o])overlapintheF1dimension,inbroadcastspeech

Does[ɨ]centralizeonlyinshorttokens?No.Correla5onofZ(F1)withdura5onisnotsignificant(p>0.05).

Fricative Liquid Nasal Stop-2

-1

0

1

2

-101 -101 -101 -101Z-scored F2

Z-sc

ored

F1

vowel � �

Following manner in broadcast speech

Fricative Liquid Nasal Stop-2

-1

0

1

-2-1012 -2-1012 -2-1012 -2-1012Z-scored F2

Z-sc

ored

F1

vowel � �

Following manner in broadcast speech

Inbroadcastspeech,[ɨ]centralizesmostinpre-nasalcontexts

Lab Broadcast-2

-1

0

1

2

0.1 0.2 0.3 0.4 0.1 0.2 0.3 0.4Vowel Duration (sec)

Vow

el F

1 (Z

-sco

red)

vowel��

Lab Broadcast-2

-1

0

1

20.1 0.2 0.3 0.4 0.5 0.1 0.2 0.3 0.4 0.5

Vowel Duration (sec)

Vow

el F

1 (Z

-sco

red)

vowel��