voice onset time as a parameter for identification of bilinguals claire gurski university of western...

Voice Onset Time as a Voice Onset Time as a Parameter for Parameter for

Identification of Identification of BilingualsBilinguals

Claire GurskiClaire Gurski

University of Western OntarioUniversity of Western Ontario

London, ON CanadaLondon, ON Canada

IntroductionIntroduction

A recording may be made in one A recording may be made in one languagelanguage

Suspect refuses to speak that languageSuspect refuses to speak that language

Can voice onset time be used as a Can voice onset time be used as a parameter for identification when cross parameter for identification when cross

language comparison materials are language comparison materials are presented?presented?

BackgroundBackground

Voice Onset Time (VOT): Voice Onset Time (VOT): ‘The interval between ‘The interval between the release of a stop the release of a stop consonant occlusion consonant occlusion and the onset of the and the onset of the vocal-fold vibration’ and vocal-fold vibration’ and is measured ‘from is measured ‘from acoustic displays as the acoustic displays as the time between the time between the release burst and the release burst and the first quasi-periodicity in first quasi-periodicity in the acoustic signal’. the acoustic signal’. (Keating, 1984) (Keating, 1984)

Time (s)25.2286 25.3076

0

8000

Time (s)25.2286 25.3076

0

8000

Time (s)25.2286 25.3076

0

8000

Time (s)25.2286 25.3076

0

8000

Time (s)25.2286 25.35

0

8000

Time (s)25.2286 25.33

0

8000

Burst VOT Beginning of Vocal-fold

vibration

Voice Onset TimeVoice Onset Time

VOT – Language SpecificVOT – Language Specific The VOT of stop consonants [p b t d k g] The VOT of stop consonants [p b t d k g]

differs between languagesdiffers between languages ‘‘Plus/minus values of the voicing feature Plus/minus values of the voicing feature

will have different quantitative VOT values will have different quantitative VOT values in different languages.’ (Keating, 1984)in different languages.’ (Keating, 1984)

Eg. [p] in French has a VOT similar to a [b] Eg. [p] in French has a VOT similar to a [b] in English in English

LanguageLanguage Voiceless Voiceless PlosivesPlosives

Voiced PlosivesVoiced Plosives

EnglishEnglish Positive VOTPositive VOT Zero VOTZero VOT

FrenchFrench Zero VOTZero VOT Negative VOTNegative VOT

VOT and Identification?VOT and Identification?

Does a person who learns a second language Does a person who learns a second language acquire a native-like VOT in their second acquire a native-like VOT in their second language or does their native language have language or does their native language have an influence? an influence?

Does a person have a consistent VOT across Does a person have a consistent VOT across languages regardless of differences between languages regardless of differences between the two languages? the two languages?

Is VOT a factor that can be used to help Is VOT a factor that can be used to help identify voices as being from the same identify voices as being from the same speaker even if they are in two different speaker even if they are in two different languages? languages?

Methodology - 2 studiesMethodology - 2 studiesStudy 1Study 1 Eight bilingual speakers – 4 Native Eight bilingual speakers – 4 Native

French and 4 Native EnglishFrench and 4 Native English 2 paragraphs – one beginning in 2 paragraphs – one beginning in

English and ending in French and one English and ending in French and one beginning in French and ending in beginning in French and ending in EnglishEnglish

Each paragraph read 4 timesEach paragraph read 4 times Participants did not have the influence Participants did not have the influence

of other languages.of other languages.

Participants – Study 1Participants – Study 1

Participant Participant NumberNumber

First LanguageFirst Language Second LanguageSecond Language

2020 FrenchFrench EnglishEnglish


2222 EnglishEnglish FrenchFrench






Analysis – Study 1Analysis – Study 1

Only intervocalic stops were analyzed to Only intervocalic stops were analyzed to eliminate the differences due to aspirated or eliminate the differences due to aspirated or unreleased stopsunreleased stops

We found minimal variation between the We found minimal variation between the languages in each of the paragraphs ie. languages in each of the paragraphs ie. English of the first paragraph and English of English of the first paragraph and English of the second paragraphthe second paragraph

Stats calculated based on the language of use Stats calculated based on the language of use – not its position in relation to the other – not its position in relation to the other languagelanguage

Study 1 - Bilingual VOTStudy 1 - Bilingual VOTVOT

p t k b d g-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

Consonants

Tim

e (

se

c.)

part 20 F part 20 E part 21 F part 21 Epart 22 F part 22 E part 23 F part 23 Epart 24 F part 24 E part 25 F part 25 Epart 26 F part 26 E part 27 F part 27 E

Hybrid SystemHybrid System

For 7 out of 8 of the speakers, their VOT does not For 7 out of 8 of the speakers, their VOT does not pattern with either the French or the English systemspattern with either the French or the English systems

Participants reacted similarly regardless of native Participants reacted similarly regardless of native languagelanguage

Hybrid system createdHybrid system created

LanguageLanguage Voiceless Voiceless plosivesplosives

Voices plosivesVoices plosives



BilingualBilingual Positive VOTPositive VOT Negative VOTNegative VOT

Hybrid VOT System of Hybrid VOT System of BilingualsBilinguals

French

voiced

voiceless

English

voiced

voiceless

VOT positive

VOT zero

VOT negative

bilinguals

VOT and variation between VOT and variation between languageslanguages

T scores – do the VOTs of the two T scores – do the VOTs of the two languages of Bilingual individuals languages of Bilingual individuals differ enough the be significantly differ enough the be significantly different/distinct in the two different/distinct in the two languages?languages?

Does their VOT pattern similarly in Does their VOT pattern similarly in both languages?both languages?

T test significance scoresT test significance scoresParticipantParticipant pp bb tt dd kk gg

20 – Fr/Eng20 – Fr/Eng 0.5600.560 0.1550.155 0.0550.055 0.6730.673 0.3320.332 0.1560.156

21 – Fr/Eng21 – Fr/Eng 0.0800.080 0.6480.648 0.3280.328 0.5340.534 0.6780.678 0.0840.084

22 – Eng/Fr22 – Eng/Fr 0.1120.112 0.0760.076 0.0000.000 0.0050.005 0.1100.110 0.4500.450

23 – Eng/Fr23 – Eng/Fr 0.3470.347 0.2800.280 0.0040.004 0.3290.329 0.9610.961 0.6860.686

24 – Fr/Eng24 – Fr/Eng 0.8490.849 0.3200.320 0.0140.014 0.2190.219 0.9540.954 0.7140.714

25 – Fr/Eng25 – Fr/Eng 0.8380.838 0.9540.954 0.4630.463 0.1580.158 0.3320.332 0.0520.052

26 – Eng/Fr26 – Eng/Fr 0.1560.156 0.0000.000 0.2280.228 0.4260.426 0.0040.004 0.0010.001

27 – Eng/Fr27 – Eng/Fr 0.0750.075 0.1100.110 0.6290.629 0.5530.553 0.1470.147 N/AN/A

Generally, the difference between the French and English VOT of Bilingual speakers does not vary considerably when they change languages

Questions to addressQuestions to address

How does the VOT of Bilingual How does the VOT of Bilingual speakers compare to that of speakers compare to that of Monolingual speakersMonolingual speakers

Are there significant differences Are there significant differences statistically that would allow for statistically that would allow for identification?identification?

Methodology - 2 studiesMethodology - 2 studies

Study 2Study 2 4 Monolingual French Speakers4 Monolingual French Speakers 4 Monolingual English Speakers4 Monolingual English Speakers Read ‘The North Wind and the Sun’ 2 Read ‘The North Wind and the Sun’ 2

times in their native languagetimes in their native language Described a comic for spontaneous Described a comic for spontaneous

production (not analyzed for this production (not analyzed for this study)study)

Participants – Study 2Participants – Study 2

The VOT of the Monolingual speakers was The VOT of the Monolingual speakers was compared to that of the Bilingual speakers compared to that of the Bilingual speakers from Study 1from Study 1

ParticipaParticipantnt

LanguagLanguagee

ParticipaParticipantnt

LanguagLanguagee

11 FrenchFrench 1616 EnglishEnglish




Analysis – Study 2Analysis – Study 2

Only intervocalic stops were Only intervocalic stops were analyzed to eliminate the differences analyzed to eliminate the differences due to aspirated or unreleased stopsdue to aspirated or unreleased stops

Smaller samples were recorded Smaller samples were recorded decreasing the number of tokensdecreasing the number of tokens

Controlled environment with Marantz Controlled environment with Marantz recording equipmentrecording equipment

Study 2 – Monolingual VOTStudy 2 – Monolingual VOT

The VOT of The VOT of Monolingual Monolingual speakers follows speakers follows the general the general patterns of French patterns of French and Englishand English

French and English VOT

p kt b d g-0.10

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

Consonants

Tim

e

Part 1 F

Part 2 F

Part 6 F

Part 7 F

Part 16 E

Part 17 E

Part 18 E

Part 19 E

LanguageLanguage Voiceless PlosivesVoiceless Plosives Voiced PlosivesVoiced Plosives



Statistical AnalysisStatistical Analysis

ANOVA tests comparing the groups – ANOVA tests comparing the groups – Monolingual English, French and Monolingual English, French and Bilingual French/English and Bilingual French/English and English/FrenchEnglish/French Are the groups significantly distinct?Are the groups significantly distinct?

ANOVA – Four Groups Eng, Fr, ANOVA – Four Groups Eng, Fr, Eng/Fr, Fr/EngEng/Fr, Fr/Eng

All are significant All are significant (except g – but only a (except g – but only a limited number of limited number of tokens)tokens)

Therefore, there is a Therefore, there is a difference between difference between the VOT of English, the VOT of English, French, English/French French, English/French Bilinguals and Bilinguals and French/English French/English BilingualsBilinguals

FactorFactor SignificancSignificancee

pp .049 .049

bb .000.000

tt .015.015

dd .051.051

kk .025.025

gg .100.100

ANOVA – English Monolinguals ANOVA – English Monolinguals with French Monolingualswith French Monolinguals

The difference in The difference in VOT of English and VOT of English and French Monolinguals French Monolinguals is significant in all is significant in all casescases

There were no There were no occurrences of occurrences of intervocalic p so intervocalic p so inferences are made inferences are made based on the other based on the other voiceless plosivesvoiceless plosives


bb .000.000

tt .004.004

dd .001.001

kk .052.052

gg .034.034

ANOVA – Fr/Eng Bilinguals with ANOVA – Fr/Eng Bilinguals with Eng/Fr Bilinguals Eng/Fr Bilinguals

The averages of their French The averages of their French and English tokens.and English tokens.

The only significant is b but if The only significant is b but if you look at the numbers, only you look at the numbers, only participant 22 deviated and participant 22 deviated and this would cause the this would cause the significance.significance.

-.051924-.051924-.054261-.054261-.008036-.008036-.033747-.033747-.046522-.046522-.054442-.054442-.027603-.027603-.024800-.024800

Because there are no other Because there are no other significant differences this significant differences this shows that the bilingual shows that the bilingual speakers pattern similarly speakers pattern similarly regardless of first languageregardless of first language


pp .216.216

bb .003 .003

tt .906.906

dd .428.428

kk .511.511

gg .290.290

ANOVA – French and English of ANOVA – French and English of Fr/Eng and Eng/Fr Bilinguals Fr/Eng and Eng/Fr Bilinguals

There are no There are no significant differences significant differences between the French between the French and English of and English of Bilingual speakersBilingual speakers

Therefore the VOT of Therefore the VOT of Second language Second language learners does not learners does not vary considerably vary considerably between their two between their two languageslanguages


pp .195.195

bb .283.283

tt .251.251

dd .990.990

kk .508.508

gg .968.968

ANOVA – Eng with Eng/Fr ANOVA – Eng with Eng/Fr BilingualsBilinguals

The English The English Monolingual Monolingual Speakers are not Speakers are not significantly significantly different from the different from the average of the average of the English/French English/French BilingualsBilinguals


bb .045.045

tt .564.564

dd .790.790

kk .324.324

gg .895.895

ANOVA – Eng with Eng of ANOVA – Eng with Eng of Eng/Fr Bilinguals Eng/Fr Bilinguals

The English of The English of English/French English/French Bilingual speakers Bilingual speakers is not significantly is not significantly different from the different from the English of English of monolingual monolingual speakersspeakers


bb .460.460

tt .322.322

dd .682.682

kk .901.901

gg .586.586

ANOVA – Eng with Eng of ANOVA – Eng with Eng of Fr/Eng Bilinguals Fr/Eng Bilinguals

The voiced stops are The voiced stops are significantly different significantly different between English between English monolingual speakers monolingual speakers and the English of and the English of native French speakers. native French speakers.

French/English bilingual French/English bilingual speakers do not acquire speakers do not acquire a native like English a native like English VOTVOT

If offender has a native If offender has a native like English VOT and like English VOT and suspect does not, may suspect does not, may be an indication be an indication towards a non-towards a non-identificationidentification


bb .001.001

tt .692.692

dd .051.051

kk .986.986

gg .005.005

ANOVA – Fr with Fr/Eng ANOVA – Fr with Fr/Eng Bilinguals Bilinguals

French with Fr/Eng French with Fr/Eng Bilinguals is generally Bilinguals is generally significant but English significant but English with Eng/Fr Bilinguals with Eng/Fr Bilinguals is notis not

The French Bilingual The French Bilingual speakers vary from speakers vary from the monolingual the monolingual French pattern which French pattern which is not the case for is not the case for their English their English counterparts.counterparts.


pp .009.009

bb .007.007

tt .008.008

dd .074.074

kk .038.038

gg .305.305

ANOVA – Fr with Fr of Fr/Eng ANOVA – Fr with Fr of Fr/Eng Bilinguals Bilinguals

In each case (disregard In each case (disregard g due to limited g due to limited tokens) the French tokens) the French VOT of the bilinguals is VOT of the bilinguals is significantly different significantly different from the French of from the French of Monolingual speakersMonolingual speakers

This is to be expected This is to be expected since Bilingual Fr/Eng since Bilingual Fr/Eng speakers range from speakers range from Positive to negative in Positive to negative in their VOTtheir VOT


pp .006.006

bb .014.014

tt .002.002

dd .035.035

kk .032.032

gg .161.161

ANOVA – Fr with Fr of Eng/Fr ANOVA – Fr with Fr of Eng/Fr Bilinguals Bilinguals

Again we have Again we have significant differences significant differences between the French of between the French of Monolingual speakers Monolingual speakers and the French of and the French of Second language Second language speakersspeakers

[d] and [g] are not [d] and [g] are not significant but again, significant but again, participant 22 who is participant 22 who is the only outlier may be the only outlier may be causing this causing this insignificanceinsignificance


pp .006.006

bb .008.008

tt .027.027

dd .135.135

kk .007.007

gg .092.092

ConclusionsConclusions There is still much research to be done There is still much research to be done

before VOT can be deemed useful in a before VOT can be deemed useful in a forensic situationforensic situation

Use of Hybrid system regardless of native Use of Hybrid system regardless of native languagelanguage

LanguageLanguage Voiceless Voiceless plosivesplosives

Voices plosivesVoices plosives



BilingualBilingual Positive VOTPositive VOT Negative VOTNegative VOT

ConclusionsConclusions Generally, VOT does not vary Generally, VOT does not vary

significantly between the languages of significantly between the languages of Bilingual speakers Bilingual speakers This is to say that the VOTs of a /p/ spoken This is to say that the VOTs of a /p/ spoken

by a bilingual speaker in French or English by a bilingual speaker in French or English will have not be significantly different will have not be significantly different

There are significant differences There are significant differences between the languages of Bilingual between the languages of Bilingual speakers and that of their Monolingual speakers and that of their Monolingual counterpartscounterparts

Areas of Further ResearchAreas of Further Research Continued Statistical AnalysisContinued Statistical Analysis Age of language learningAge of language learning Level of fluencyLevel of fluency Multilingual or bilingual in other languagesMultilingual or bilingual in other languages Effects of nervousnessEffects of nervousness Reading vs. Spontaneous speechReading vs. Spontaneous speech Effects of the telephoneEffects of the telephone Canadian French affricationCanadian French affrication Larger number of participants with similar Larger number of participants with similar

voice qualitiesvoice qualities Vocal DisguiseVocal Disguise

voice onset time as a parameter for identification of bilinguals claire gurski university of western...

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