1. INTRODUCTION
⌅Plosives
are, as a group, the most common consonants in the languages of the
world, and the greater part of world languages have voiceless plosives (Ladefoged & Maddieson, 1996Ladefoged, P., & Maddieson, I. (1996). The sounds of the world’s languages. Blackwell.
; Maddieson, 1984Maddieson, I. (1984). Patterns of sounds. Cambridge University Press.
). More specifically, Moran and McCloy (2019)Moran, S., & McCloy, D. (2019). Phoible 2.0. Max Planck Institute for the Science of Human History. Available online at http://phoible.org, Accessed on 21 May 2023.
found that /p/ had an 86% frequency in the languages they surveyed
(2,186 languages); the frequencies for /t/ and /k/ were 68% and 90%
respectively. A crucial characteristic that contrasts voiceless plosives
among the languages of the world is their voice onset time (VOT) (e.g., Hayward, 2000Hayward, K. (2000). Experimental phonetics. Pearson Education.
).
This refers to the time that elapses between the release of the plosive
and the onset of vocal fold vibration (of the following vowel or
approximant). There are three types of VOT: negative VOT, zero VOT, and
positive VOT. The latter type can be further subdivided into long and
short positive VOT; plosives with a long positive VOT are said to be
aspirated (e.g., Wayland, 2019Wayland, R. (2019). Phonetics: A practical introduction. Cambridge University Press.
).
The release stage of the plosive is evidenced acoustically by a burst
or transient on the waveform, and a plosion bar on the spectrogram. As
noted by Bóna and Auszmann (2014)Bóna,
J., & Auszmann, A. (2014). Voice onset time in language
acquisition: Data from Hungarian. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 41-44). Cologne, Germany. /http://real.mtak.hu/15397/1/BA_VOT.pdf
and Ladefoged (2003)Ladefoged, P. (2003). Phonetic data analysis: An introduction to fieldwork and instrumental techniques. Blackwell.
,
among others, measuring VOT is often marred with complications. One of
them is that voiceless plosives can be released in multiple stages, thus
producing multiple bursts (MBs). Figure 1 displays the production of the initial plosive in the word kids by a non-native speaker of English with Hindi as his first language
(L1). The velar has two transients (as shown on the waveform) and two
corresponding plosion bars (shown on the spectrogram.
A few explanations for the production of MBs have been advanced. According to Plauché (2001)Plauché,
M. (2001). Acoustic cues in the directionality of stop consonant
confusions [Doctoral dissertation]. University of California, Berkeley,
United States of America. https://escholarship.org/uc/item/8hz6k4c2
, this phenomenon may be due to rapid intraoral
pressure during closure, which lowers abruptly upon the release of the
plosive, producing multiple transients. As will be illustrated later
(see sections 1.1 and 1.2), velar plosives have been shown to present
many more MBs than other places of articulation (PoAs). Song, Demuth, and Shattuck-Hufnagel (2012)Song,
J. Y., Demuth, K., & Shattuck-Hufnagel, S. (2012). The development
of acoustic cues to coda contrasts in young children learning American
English. Journal of the Acoustical Society of America, 131(4), 3036-3050. https://pubs.aip.org/asa/jasa/article-abstract/131/4/3036/830852/The-development-of-acoustic-cues-to-coda-contrasts?redirectedFrom=fulltext
and Plauché (2001)Plauché,
M. (2001). Acoustic cues in the directionality of stop consonant
confusions [Doctoral dissertation]. University of California, Berkeley,
United States of America. https://escholarship.org/uc/item/8hz6k4c2
explain that this phenomenon may result from the
large area of the velar obstruction and its accompanying slow release,
which gives rise to multiple burst releases. Plauché (2001)Plauché,
M. (2001). Acoustic cues in the directionality of stop consonant
confusions [Doctoral dissertation]. University of California, Berkeley,
United States of America. https://escholarship.org/uc/item/8hz6k4c2
also notes that some researchers have posited
that the closure stage may be conditioned by the Bernoulli force,
whereby the quick airflow initiation creates negative pressure at the
obstruction place.
To reiterate, aspiration can only be analyzed
by measuring the VOT of the plosive, and, as is in many occasions the
case when voiceless plosives are produced with MBs, complications arise.
In the presence of MBs, it has to be decided whether VOT measurement
will be made from the first burst or the last burst (or some other
point, see Gráczi & Kohári, 2014Gráczi,
T. E., & Kohári, A. (2014). Multiple bursts in Hungarian voiceless
plosives and VOT measurements. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 158-161). Cologne, Germany. /https://www.researchgate.net/profile/Anna-Kohari/publication/305635295_Multiple_bursts_in_Hungarian_voiceless_plosives_and_VOT_measurements/links/579648c508aed51475e54c81/Multiple-bursts-in-Hungarian-voiceless-plosives-and-VOT-measurements.pdf
). Prior research has determined that different
methods produce statistically significant disparate VOT durations, and
that factors such as PoA, vowel height, and speech rate have an effect
on MBs to varying degrees (Barrera-Pardo, 2022Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
). In line with these past findings, the aim of
the current study is to analyze MBs in non-native English and establish a
comparison with native English. First, it explores whether VOT values
are affected when measuring VOT from the first or last burst. Second, it
investigates the effect of PoA, gender, speech rate, and age on MBs.
MBs
have been identified in various languages, although few researchers
have quantified them systematically (notable exceptions are Gráczi & Kohári, 2014Gráczi,
T. E., & Kohári, A. (2014). Multiple bursts in Hungarian voiceless
plosives and VOT measurements. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 158-161). Cologne, Germany. /https://www.researchgate.net/profile/Anna-Kohari/publication/305635295_Multiple_bursts_in_Hungarian_voiceless_plosives_and_VOT_measurements/links/579648c508aed51475e54c81/Multiple-bursts-in-Hungarian-voiceless-plosives-and-VOT-measurements.pdf
, for Hungarian; Barrera-Pardo, 2022Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
, and Lavoie, 2001Lavoie, L.M. (2001). Consonant strength: Phonological patterns and phonetic manifestations. Routledge.
, both for Spanish). The following sections review research on MBs in English and other languages.
1.1. MBs in English
⌅ Lavoie (2001)Lavoie, L.M. (2001). Consonant strength: Phonological patterns and phonetic manifestations. Routledge.
found in her North American English data MBs for /p/ (6 MBs), /t/ (1
MB), and /k/ (25 MBs). Interestingly, she reported many more MBs for the
voiced plosives (11 for /b/, 9 for /d/, and 29 for /g/). In both
voiceless and voiced plosives she analyzed 30 tokens per consonant, and
the reported figures refer to the total number of MBs.
Repp and Lin (1989)Repp, B.H., and Lin, H-B. (1989). Acoustic properties and perception of stop consonant release transients. Journal of the Acoustical Society of America, 85(1), 379-396. https://pubs.aip.org/asa/jasa/article-abstract/85/1/379/969397/Acoustic-properties-and-perception-of-stop?redirectedFrom=fulltext
, for the same variety, found that MBs were common
for alveolars and velars in back vowel contexts, and that MBs were
always present for velars in front vowel contexts. A few cases of double
bursts involving bilabials were also reported. They also found that, in
spontaneous speech, MBs especially for velars were much less frequent.
These researchers further noted that vowel type, speaker identity, and
gender did not statistically affect the number of bursts, whereas PoA
did. Like other studies, Parveen and Goberman (2012)Parveen, S., & Goberman, A.M. (2012). Presence of stop bursts and multiple bursts in younger and older adults. Asia Pacific Journal of Speech, Language, and Hearing, 15(4), 265-275. https://www.tandfonline.com/doi/abs/10.1179/136132812804731811
, also for North American English, reported a
significant effect of MBs across PoA, such that velars had the highest
number of MBs, followed by alveolars and then bilabials. Sučková (2020)Sučková, M. (2020). First language attrition in voice onset times in Anglophone expatriates residing in the Czech Republic. Brno Studies in English, 46(2), 47-66. https://digilib.phil.muni.cz/en/handle/11222.digilib/143206
investigated VOTs of North American
English-speaking residents in a Czech language context, noting the
presence of MBs, although she did not quantify them. For Australian
English, Millasseau et al. (2019)Millasseau,
J., Bruggeman, L., Yuen, I., & Demuth, K. (2019). Durational cues
to place and voicing contrasts in Australian English word-initial stops.
In S. Calhoun, P. Escudero, M. Tabain, & P. Warren (Eds.), Proceedings of the 19th International Congress of Phonetic Sciences (pp. 3759-3762). Canberra: Australasian Speech Science and Technology Association Inc. https://www.internationalphoneticassociation.org/icphs-proceedings/ICPhS2019/papers/ICPhS_3808.pdf
also reported finding MBs in the production of plosives. Imbrie (2005)Imbrie, A. K. K. (2005). Acoustical study of the development of stop consonants in children. [Doctoral dissertation]. Massachusetts Institute of Technology, United States of America. https://dspace.mit.edu/handle/1721.1/33072
investigated the development of plosive
production in North American English-speaking children. She determined
that children produced more bursts than adults, with a statistically
significant difference. Again, and as in prior research, the effect of
PoA on the number of bursts was statistically significant, with velars
presenting the highest number of bursts, and bilabials the least.
1.2. MBs in other languages
⌅MBs have been attested for languages other than English. Yang (2018)Yang, J. (2018). Development of stop consonants in three- to six-year-old Mandarin-speaking children. Journal of Child Language, 45, 1091-1115. DOI: https://doi.org/10.1017/S030500918000090
determined that in Mandarin velars had more MBs
than the alveolars and bilabials. The vowel context was found to have an
effect on the number of bursts, whereby plosives followed by /i/
presented significantly more MBs than plosives before /a/ or /u/. In
Spanish, Torres and Iparraguirre (1996)Torres,
M. I., & Iparraguirre, P. (1996). Acoustic parameters for place of
articulation identification and classification of Spanish unvoiced
stops. Speech Communication, 18, 369-379. https://www.sciencedirect.com/science/article/abs/pii/0167639396000258
observed MBs for /k/. Asensi, Portolés, & del Río (1997)Asensi, L. Portolés, S., & del Río, A. (1997). Barra de explosión, VOT y frecuencia de las oclusivas sordas del castellano. Estudios de Fonética Experimental, IX, 221-242. /https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/EFE-IX-LlAsensi_SPortoles_AdelRio-Barra_explosion_VOT_frecuencia_oclusivas_sordas.pdf
studied the plosives of Castilian Spanish,
finding in their analyses that especially the velar had MBs, which had
double and triple plosion bars, whereas /t/ presented double bars. Lavoie (2001)Lavoie, L.M. (2001). Consonant strength: Phonological patterns and phonetic manifestations. Routledge.
reported for Mexican Spanish numerous MBs for /k/ (31), whereas she found only 1 for /t/ and none for /p/. Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
, analyzing the voiceless plosives of Western
Andalusian Spanish, reported MBs across all three PoAs. 9.5% of
bilabials had MBs, and the percentages for /t/ and /k/ were 15.22% and
33.33% respectively. The velar presented up to 5 bursts. Vowel context
had a statistically significant effect on MBs, such that high vowels
triggered more bursts.
MBs have also been reported for Hindi. Sirsa and Redford (2013)Sirsa, H., & Redford, M.A. (2013). The effects of native language on Indian English sounds and timing patterns. Journal of Phonetics, 41, 393-406. https://www.sciencedirect.com/science/article/abs/pii/S0095447013000399
found MBs in the measurement of VOT for voiceless plosives of Hindi. Davis (1994)Davis, K. (1994). Stop voicing in Hindi. Journal of Phonetics, 22, 177-193. https://www.sciencedirect.com/science/article/pii/S0095447019301925
reported that velars in this language very frequently presented MBs. In Brazilian Portuguese, Michelon Melo et al. (2014)Michelon
Melo, R., Bolli Mota, H., Lisbôa Mezzomo, C., de Castro Brasil, B.,
Lovatto, L, & Arzeno, L. (2014). Acoustic characterization of the
voicing of stop phones in Brazilian Portuguese. Revista CEFAC, 16(2), 487-499. https://www.scielo.br/j/rcefac/a/ZB9NzFyfJxgHCpK7s44RSwf/abstract/?lang=en
found MBs for both voiceless and voiced plosives. In the speech of child speakers of European Portuguese, Brinca et al. (2016)Brinca,
L. Araújo, L., Nogueira, P., & Gil, C. (2016). Voice onset time
characteristics of voiceless stops produced by children with European
Portuguese as mother tongue. Ampersand, 3, 137-142. https://www.sciencedirect.com/science/article/pii/S2215039015300114
also reported MBs for voiceless plosives. Also for European Portuguese, Lousada, Jesus, and Hall (2010)Lousada,
M. Jesus, L.M.T., & Hall, A. (2010). Temporal acoustic correlates
of the voicing contrast in European Portuguese stops. Journal of the International Phonetic Association, 40(3), 261-275. DOI: https://doi.org/10.1017/S0025100310000186
found MBs in the speech of adult speakers. A language in which MBs have been identified and further quantified is Hungarian; Gráczi and Kohári (2014)Gráczi,
T. E., & Kohári, A. (2014). Multiple bursts in Hungarian voiceless
plosives and VOT measurements. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 158-161). Cologne, Germany. /https://www.researchgate.net/profile/Anna-Kohari/publication/305635295_Multiple_bursts_in_Hungarian_voiceless_plosives_and_VOT_measurements/links/579648c508aed51475e54c81/Multiple-bursts-in-Hungarian-voiceless-plosives-and-VOT-measurements.pdf
determined that nearly 48% of the voiceless
plosives they analyzed presented MBs: 27.5% of the bilabials had MBs,
whereas the percentages for /t/ and /k/ were 45% and 66.4% respectively.
They also reported that the height of the vowel following the plosive
had no effect on the number of bursts, except for /k/, which, when
followed by /i/, presented at least two bursts in 77.5% of the
productions. For Czech, Kaňok and Novotný (2019)Kaňok, M., & Novotný, M. (2019). Effect of age and gender on articulation of voiced and voiceless stop consonants in Czech. Lekar a Technika: Clinician and Technology, 49(3), 97-101. https://ojs.cvut.cz/ojs/index.php/CTJ/article/view/5957
reported MBs in their analysis of the effects of
age and gender on the plosives of this language. They reported MBs as
occurring in their analyses, but no further quantification was offered.
In summary, PoA emerges as a powerful factor in the production of MBs, such that, according to most researchers, bilabial consonants have fewer MBs than alveolars, and these in turn present fewer MBs than velars. The pattern when quantifying MBs then appears to be /p/ < /t/ < /k/.
1.3. VOT measurement in the presence of MBs
⌅MBs complicate VOT measurement (e.g., Foulkes, Docherty, & Jones, 2010Foulkes, P., Docherty, G, & Jones, M. (2010). Analyzing stops. In M. Di Paolo, & M. Yaeger-Dror (Eds.), Sociophonetics: A student’s guide (pp. 58-71). Routledge.
). A number of methods may be employed to measure VOT in the presence of MBs (see Barrera-Pardo, 2022Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
for a review), although most researchers seem to
take the first burst as the measurement point: 24 (63%) of the 38
studies reviewed by Barrera-Pardo chose this method. It is noteworthy,
nonetheless, that only Gráczi and Kohári (2014)Gráczi,
T. E., & Kohári, A. (2014). Multiple bursts in Hungarian voiceless
plosives and VOT measurements. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 158-161). Cologne, Germany. /https://www.researchgate.net/profile/Anna-Kohari/publication/305635295_Multiple_bursts_in_Hungarian_voiceless_plosives_and_VOT_measurements/links/579648c508aed51475e54c81/Multiple-bursts-in-Hungarian-voiceless-plosives-and-VOT-measurements.pdf
and in more detail Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
have investigated the effect of choosing a
particular method when measuring VOT (first or last burst, in both
studies). The results reported by these researchers suggest that this
decision may be crucial for VOT measurement.
1.4. MBs and gender
⌅ Plauché (2001)Plauché,
M. (2001). Acoustic cues in the directionality of stop consonant
confusions [Doctoral dissertation]. University of California, Berkeley,
United States of America. https://escholarship.org/uc/item/8hz6k4c2
investigated the acoustic cues that are used to
identify the PoA of plosives; she determined that the number of bursts
did not vary statistically significantly by speaker gender. Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
found that in a Spanish variety (Western
Andalusian), gender did not play a role in the number of bursts that the
voiceless plosives of this dialect presented.
1.5. MBs and speech rate
⌅ Sönmez et al. (2000)Sönmez,
K., Plauché, M., Shriberg, E., & Franco, H. (2000). Consonant
discrimination in elicited and spontaneous speech: A case for
signal-adaptive front ends in ASR. Sixth International Conference on Spoken Language Processing, ICSLP 2000 / INTERSPEECH 2000. Beijing, China. https://www.isca-speech.org/archive/pdfs/icslp_2000/sonmez00_icslp.pdf
offered data that suggest that in spontaneous
speech (with a concomitant faster speech rate), MBs were less numerous
than in elicited speech. However, Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
reported a very weak and marginally significant (ρ = 0.15, p = 0.8) correlation between speech rate and the number of bursts
produced, such that a faster speech rate appeared to be related to a
larger number of bursts. Similarly, Wang et al. (2004)Wang,
Y-T., Kent, R. D., Duffy, J. R., Thomas, J. E., & Weismer, G.
(2004). Alternating motion rate as an index of speech motor disorder in
traumatic brain injury. Clinical Linguistics & Phonetics, 18(1), 57-84. https://www.tandfonline.com/doi/abs/10.1080/02699200310001596160
found that patients with traumatic brain injury who spoke at a faster speech rate produced more MBs.
1.6. MBs and age
⌅For Mandarin, Yang (2018)Yang, J. (2018). Development of stop consonants in three- to six-year-old Mandarin-speaking children. Journal of Child Language, 45, 1091-1115. DOI: https://doi.org/10.1017/S030500918000090
examined developmental data of children, finding
that children produced significantly more MBs than adults, a pattern
that corroborated Imbrie’s (2005)Imbrie, A. K. K. (2005). Acoustical study of the development of stop consonants in children. [Doctoral dissertation]. Massachusetts Institute of Technology, United States of America. https://dspace.mit.edu/handle/1721.1/33072
findings for English plosives. Parveen and Goberman (2012)Parveen, S., & Goberman, A.M. (2012). Presence of stop bursts and multiple bursts in younger and older adults. Asia Pacific Journal of Speech, Language, and Hearing, 15(4), 265-275. https://www.tandfonline.com/doi/abs/10.1179/136132812804731811
explored MBs in younger and older adult speakers.
They did not find statistically significant differences between PoA and
age group; the effect of age group on the number of bursts was not
statistically significant either.
1.7. Research questions
⌅The current study investigates the production of MBs by non-native English speakers of twelve different L1s, as further explained in section 2.1. It further compares non-native productions with native productions of MBs. Given the findings presented in the preceding sections, it is hypothesized, first, that measuring VOT either from the first or last burst will produce markedly different VOT values for the three voiceless plosives analyzed (/p/, /t/, /k/). Second, it is expected that the number of MBs will be influenced by PoA, speech rate, and perhaps age; speaker gender, however, is not expected to play a role in the number of MBs. The present study seeks to answer the following research questions:
2. THE STUDY
⌅The
data for this study were collected from native and non-native speakers
of English with twelve different L1s. Native speaker data were collected
to compare VOT measurement method in the presence of MBs and the
effects of PoA, speech rate, age, and gender with non-native data. The
selected L1s were listed as having the most native speakers in the world
(Ethnologue, 2022Ethnologue. (2022). Available online at https://www.ethnologue.com/, Accessed on 2 February 2023.
);
the languages are Mandarin, Spanish, Hindi, Bengali, Portuguese,
Russian, Japanese, Vietnamese, Turkish, Korean, Farsi (Persian), and
German. Arabic was excluded because this language does not have /p/ in
its phonological inventory.
2.1. Speakers
⌅The speaker characteristics are listed in Table 1.
These speakers were selected for VOT and MB scrutiny according to their
feasibility for acoustic analysis; recordings of poor quality were
hence discarded. One of the biographical data reported in the Speech Accent Archive (see below section 2.2) is length of English residence (LOR; range 0 -
58), which was not included in the current study, since a non-parametric
Spearman correlation between LOR and the number of bursts yielded a
negligible and non statistically significant relationship (ρ = 0.07, p = 0.09). The Speech Accent Archive does not report speaker’s level of English, but it does report English
learning method (academic or naturalistic) and age of English learning
onset. Speakers were thus chosen so that they had learned English in an
academic setting and had started learning English after puberty (i.e.,
older than 12 years); the latter is a variable that has long been known
to determine accented speech (e.g., Flege, 1981Flege, J. E. (1981). The phonological basis of foreign accent: A hypothesis. TESOL Quarterly, 15(4), 443-455. https://doi.org/10.2307/3586485
). Foreign-accented speech was evident in all the
recorded samples chosen for further acoustic analysis. Thus, for the
purposes of the current study, the non-native speakers evidenced
equivalent characteristics. Regarding age, the range for the native
speakers was 18 - 86, similar to the non-native speakers’ range (18 -
84). There were roughly the same number of females and males in both
groups of speakers, non-native and native.
L1 | N | Mage | SDage | Female | Male |
---|---|---|---|---|---|
English | 125 | 39.3 | 19.8 | 59 | 66 |
Bengali | 14 | 29.8 | 13.39 | 7 | 7 |
Farsi | 15 | 29.1 | 11.70 | 8 | 7 |
German | 15 | 35.3 | 11.11 | 9 | 6 |
Hindi | 15 | 31.2 | 11.52 | 6 | 9 |
Japanese | 15 | 41.4 | 19.54 | 8 | 7 |
Korean | 15 | 31.9 | 13.88 | 7 | 8 |
Mandarin | 15 | 31.6 | 8.99 | 9 | 6 |
Portuguese | 15 | 29.5 | 8.09 | 8 | 7 |
Russian | 15 | 37.6 | 16.02 | 8 | 7 |
Spanish | 15 | 32.9 | 10.70 | 6 | 9 |
Turkish | 15 | 25.3 | 5.96 | 7 | 8 |
Vietnamese | 15 | 35.8 | 15.28 | 6 | 9 |
Total non-native | 179 | 32.62 | 4.33 | 89 | 90 |
2.2. Material
⌅Recordings from the 125 English native speakers and the 179 non-native speakers were retrieved from the Speech Accent Archive (Weinberger, 2015Weinberger, S. (2015).Speech Accent Archive. George Mason University. Retrieved from http://accent.gmu.edu
), which houses a large sample of native and non-native speakers of English, reading the elicitation passage that follows:
Please call Stella. Ask her to bring these things with her from the store: Six spoons of fresh snow peas, five thick slabs of blue cheese, and maybe a snack for her brother Bob. We also need a small plastic snake and a big toy frog for the kids. She can scoop these things into three red bags, and we will go meet her Wednesday at the train station.
The words peas, toy, and kids were used to measure the VOT and MBs (if any) of /p, t, k/. These words were chosen because the voiceless plosives are followed by a vowel, instead of an approximant, as in please or train. Words with different phonological shapes (e.g., multisyllabic words) might yield different results (see section 5). As previously mentioned, sound files for each language and speaker were carefully inspected in order to select those of good quality for acoustic analysis. The sound files were saved and subsequently normalized for peak amplitude.
2.3. Analysis
⌅For the non-native L1s, 537 plosives were collected (3 tokens x 179 speakers). Of these, 69 plosives were discarded because they were impossible to analyze. This resulted in 468 plosives subjected to analysis: 155 bilabials, 159 alveolars, and 154 velars. For the English native speakers, 375 plosives were collected (3 tokens x 125 speakers). Of these, 43 plosives were discarded because it was not possible to analyze them. This resulted in 333 plosives subjected to analysis: 112 bilabials, 114 alveolars, and 107 velars. The release bursts of the voiceless plosives were identified on the waveform together with a wideband spectrogram. Figures 2 and 3 illustrate this procedure.
For
each plosive that presented MBs, VOT was measured from the first burst
and also from the last burst. For example, for the L1 Mandarin speaker
production of peas, shown in Figure 2,
the VOT as measured from the first burst resulted in 28 ms; when VOT
was measured from the last burst, the VOT was 22 ms. In the case of the
L1 Spanish speaker’s production of kids, shown in Figure 3,
the VOT measurement from the first burst was 62 ms, and from the last
burst it resulted in 41 ms. VOT was measured in each token from the
first and last burst, as indicated, to the beginning of periodicity, as
marked by a clear F2 of the following vowel. It was decided to measure
VOT from the last burst because, as explained by Keating et al. (1980)Keating,
P. A., Westbury, J. R., & Stevens, K. N. (1980). Mechanisms of
stop-consonant release for different places of articulation. Journal of the Acoustical Society of America, 67, S93. https://doi.org/10.1121/1.2018489
, this may be the intended one. In addition, the
number of MBs for each consonant was tallied separately for non-native
and native English. Finally, to confirm the reliability of the data
measurements (VOT, number of MBs), the author reanalyzed 25% of the data
three weeks after the first analysis, which yielded a very high
correlation between both rounds of measurements, r = 0.87, p < 0.001.
3. RESULTS
⌅3.1. Effect of measurement method of MBs on VOT
⌅Table 2 presents the descriptives related to RQ1, for non-native English. Expectedly, the VOT measurement method produced different VOT values. However, it appears that the mean differences between the first and last burst measurement were very similar for both /p/ and /t/, about 6 ms for each, whereas for /k/ the difference was much larger, about 14 ms. The spread of the values, as indicated by their SDs, was also similar in the bilabials and alveolars, although higher for these than for the velars.
Burst | Plosive | N | Mean VOT | SD |
---|---|---|---|---|
First | Bilabial | 41 | 63.61 | 30.51 |
Alveolar | 39 | 65.84 | 28.77 | |
Velar | 112 | 77.06 | 21.04 | |
Last | Bilabial | 41 | 56.82 | 30.87 |
Alveolar | 39 | 59.48 | 28.92 | |
Velar | 112 | 62.70 | 21.06 |
To
analyze in non-native English the effect of VOT measurement method
(from the first burst, or from the last burst), an ANOVA with VOT as the
dependent variable and PoA (Bilabial, Alveolar, Velar) and VOT
measurement (First burst, Last burst) as factors was planned. Prior to
running this test, the assumptions of ANOVA were checked. VOT was not
normally distributed, as evidenced by visual inspection of boxplots, and
more formally assessed by a Shapiro-Wilk test (W = 0.98, p < 0.001). Accordingly, non-parametric equivalents of ANOVA, the
Kruskal-Wallis test, were run. There was a statistically significant
effect of PoA, χ 2(2) = 41.86, p < 0.001, with a medium effect size, η 2 = 0.06 (for the interpretation of the effect size indices hereafter reported, see Cohen, 1988Cohen, J. (1988). Statistical power analysis for the behavioral sciences. 2nd ed. Lawrence Erlbaum.
). A statistically significant effect of measurement method was found, χ 2(5) = 33.62, p < 0.001, M difference = 11.12, with a medium effect size, η 2 = 0.09. Post-hoc tests with a Bonferroni correction showed
the following. For /p/, there was not a statistically significant
difference as measured from the first or last burst, M difference = 6.79, p bonferroni = 1, with a small effect size, d = 0.22; for /t/, there was not a statistically significant difference as measured from the first or last burst, M difference = 6.36, p bonferroni = 1, with a small effect size, d = 0.26; and finally, for /k/, there was a statistically significant difference as measured from the first or last burst, M difference = 14.36, p bonferroni < 0.001, with a large effect size, d = 0.72.
The descriptives for the MB measurement method for native English speakers are presented in Table 3. In this case, the mean difference of the bilabial when measured from the first or last burst was nearly 8 ms, 11.5 ms for the alveolar, and about 14 ms for the velar. Thus, the mean differences for /p/ and /t/ were higher in native English than in non-native English; /k/ had the same mean difference in non-native and native English. It should also be remarked that the SDs for the native English productions in Table 3 are on the whole lower than the SDs for the non-native English data presented in Table 2.
Burst | Plosive | N | Mean VOT | SD |
---|---|---|---|---|
First | Bilabial | 37 | 60.71 | 15.55 |
Alveolar | 18 | 83.55 | 23.37 | |
Velar | 72 | 80.52 | 15.45 | |
Last | Bilabial | 37 | 52.84 | 16.55 |
Alveolar | 18 | 72.05 | 22.70 | |
Velar | 72 | 66.34 | 16.99 |
In order to analyze in native English the effect of VOT measurement method (from the first burst, or from the last burst), an ANOVA with VOT as the dependent variable and PoA (Bilabial, Alveolar, Velar) and VOT measurement (First burst, Last burst) as factors was planned. Prior to running this test, the assumptions of ANOVA were checked. VOT was normally distributed (W = 0.99, p = 0.77), and homogeneity of variances corroborated (F(5, 250) = 1.72, p = 0.13). An ANOVA with VOT as the dependent variable and Burst measurement (First, Last), and PoA (Bilabial, Alveolar, Velar) as factors revealed a statistically significant effect of measurement method, F(1,250) = 19.69, p < 0.001, with a medium effect size, η 2 = 0.07, and a statistically significant effect of PoA, F(2,250) = 28.44, p < 0.001, η 2 = 0.18, which is a large effect size. There was a statistically nonsignificant interaction of Burst X PoA, F(2,250) = 0.83, p = 0.43, with a trivial effect size, η 2 = 0.007. Post-hoc Bonferroni-adjusted tests on this interaction showed that the following. There was a non statistically significant for /p/ according to measurement method, M difference = 7.73, p bonferroni = 0.39, with a medium effect size, d = 0.44. For /t/, with a M difference = 11.50, the difference was not statistically significant, p bonferroni = 0.35, with a medium effect size, d = 0.66. Lastly, for /k/, there was a M difference = 14.18, which was statistically significant, p bonferroni < 0.001, with a large effect size, d = 0.82.
3.2. Effects of PoA, gender, age, and speech rate on MBs
⌅3.2.1. MBs and PoA
⌅In non-native English, a total of 468 plosives were subjected to analysis. Of these, 192 had MBs (range = 2 - 5), i.e., 41% of the plosives. A chi-square test on this result yielded a statistically significant difference, χ2(1) = 111.08, p < 0.001, with a medium effect size, Phi = 0.41. 26.45% of bilabials presented MBS, 24.52% of alveolars had MBs, and 72.72% of velars had more than one burst. These differences are statistically significant, with a large effect size, χ2(4) = 191.35, p < 0.001, Cramer’s V = 0.76. In native English, a total of 333 plosives were analyzed. Of these, 256 had MBs (range = 2 - 5), that is, 76.87% of the plosives. A chi- square test on this result yielded a statistically significant difference, χ2(1) = 299.15, p < 0.001, with a very large effect size, Phi = 0.80. 33.92% of bilabials presented MBs, 15.78% of alveolars had MBs, and 67.28% of velars had more than one burst. These differences are statistically significant, with a large effect size, χ2(4) = 159.19, p < 0.001, Cramer’s V = 0.69.
The difference between non-native English and native English in the number of plosives that had MBs is statistically significant, with a medium effect size, χ2(1) = 27.95, p < 0.001, Phi = 0.38.
Table 4 shows the mean number of bursts by PoA in non-native and native English, which are almost identical for both varieties. A Kruskal-Wallis test showed that non-native and native English did not differ statistically significantly in the number of MBs, χ 2(1) = 0.19, p = 0.65, with a negligible effect size, η 2 = 0.001.
Plosive | L1 | N | Mean | SD | Min | Max |
---|---|---|---|---|---|---|
Bilabial | Non-native | 82 | 2.20 | 0.55 | 2 | 5 |
Native | 76 | 2.21 | 0.52 | 2 | 4 | |
Alveolar | Non-native | 78 | 2.08 | 0.26 | 2 | 3 |
Native | 36 | 2.28 | 0.45 | 2 | 3 | |
Velar | Non-native | 224 | 2.86 | 0.88 | 2 | 5 |
Native | 144 | 2.86 | 0.93 | 2 | 5 |
Table 5 displays the frequency of occurrence of MBs across PoA for non-native and native English. For non-native English, these differences were statistically significant, χ2(6) = 82.16, p < 0.001, Cramer’s V = 0.37, which is a medium effect size. For native English, a chi-square was also statistically significant, χ2(6) = 57.63, p < 0.001, with a medium effect size, Cramer’s V = 0.31. For the /p/, non-native and native English differed significantly in the occurrence of MBs across PoA, χ2(3) = 8.7, p = 0.03, Cramer’s V = 0.21, a small effect size. For /t/, non-native and native English differed significantly in the occurrence of MBs across PoA, χ2(3) = 13.93, p = 0.003, with a small effect size, Cramer’s V = 0.26. Finally, for /k/, non-native and native English did not differ significantly in the occurrence of MBs across PoA, χ2(3) = 0.62, p = 0.89, with a trivial effect size, Cramer’s V = 0.05.
Plosive | L1 | 2 bursts | 3 bursts | 4 bursts | 5 bursts |
---|---|---|---|---|---|
Bilabial | Non-native | 85.36 | 12.20 | 0 | 2.44 |
Native | 84.21 | 10.52 | 5.27 | 0 | |
Alveolar | Non-native | 92.31 | 7.69 | 0 | 0 |
Native | 72.22 | 27.78 | 0 | 0 | |
Velar | Non-native | 41.97 | 36.61 | 16.07 | 5.35 |
Native | 44.44 | 31.94 | 16.66 | 6.96 |
In non-native English, a Kruskal-Wallis test showed that the PoA of the plosive had a statistically significant effect on the number of MBs, χ 2(2) = 87.54, p < 0.001, with a substantial effect size, η 2 = 0.23. Post-hoc tests with a Bonferroni correction showed that there were significant differences between /p/ and /k/, p < 0.001, with large effect size, d = 0.89, and between /t/ and /k/, p < 0.001, with a very large effect size, d = 1.19. There was no statistically significant difference between /p/ and /t/, p = 0.47, with a small effect size, d = 0.27.
In native English, a Kruskal-Wallis test showed that the PoA of the plosive had a statistically significant effect on the number of MBs, χ 2(2) = 37.72, p < 0.001, with a large effect size, η 2 = 0.15. Post-hoc tests with a Bonferroni correction showed that there were significant differences between /p/ and /k/, p < 0.001, with a large effect size, d = 0.85, and between /t/ and /k/, p = 0.002, with a large effect size, d = 0.78. There was no statistically significant difference between /p/ and /t/, p = 0.39, with a small effect size, d = 0.14.
Table 6 displays the mean number of bursts by L1. A Kruskal-Wallis test showed that the L1 did not have a statistically significant effect on the number of MBs, χ 2(11) = 8.94, p = 0.62, with a small effect size, η 2 = 0.02. None of the Bonferroni-corrected post-hoc pairwise comparisons between L1s were statistically significant, all p > 0.05.
L1 | Mean bursts | SD | Min | Max |
---|---|---|---|---|
Bengali | 2.46 | 0.76 | 2 | 4 |
Farsi | 2.50 | 0.60 | 2 | 4 |
German | 2.65 | 1.02 | 2 | 5 |
Hindi | 2.38 | 0.63 | 2 | 4 |
Japanese | 2.62 | 1.01 | 2 | 5 |
Korean | 2.64 | 0.82 | 2 | 4 |
Mandarin | 2.56 | 0.70 | 2 | 4 |
Portuguese | 2.33 | 0.47 | 2 | 3 |
Russian | 2.58 | 0.97 | 2 | 5 |
Spanish | 2.53 | 0.70 | 2 | 4 |
Turkish | 2.89 | 0.75 | 2 | 4 |
Vietnamese | 2.60 | 0.87 | 2 | 5 |
3.2.2. MBs and gender
⌅Tables 7 and 8 show the mean number of bursts by gender, in non-native and native English respectively. The data indicate that the mean differences were very small. In non-native English, a Kruskal-Wallis test showed that there was no effect of gender on the number of bursts, χ 2(1) = 0.03, p = 0.85, with a trivial effect size, η 2 = 0.001. The same result was obtained for native English, χ 2(1) = 0.24, p = 0.62, η 2 = 0.001.
Gender | Female | Male |
---|---|---|
Mean | 2.58 | 2.52 |
SD | 0.85 | 0.75 |
Minimum | 2 | 2 |
Maximum | 5 | 5 |
Gender | Female | Male |
---|---|---|
Mean | 2.61 | 2.55 |
SD | 0.87 | 0.79 |
Minimum | 2 | 2 |
Maximum | 5 | 5 |
3.2.3. MBs and age
⌅A non-parametric Spearman’s rho correlation between the number of bursts and age in non-native English yielded a very weak and marginally significant effect, ρ = 0.10, p = 0.05. In native English, the association was trivial and nonsignificant, ρ = 0.03, p = 0.62.
3.2.4. MBs and speech rate
⌅Speech rate was computed as the mean number of syllables per second. In non-native English, the resulting speech rate was M = 2.88, SD = 0.63. There was no significant correlation between speech rate and the number of bursts, with a negligible effect size, ρ = 0.03, p = 0. 47; for native English, speech rate and the number of bursts were not statistically associated either, and the effect was as well trivial, M = 3.69, SD = 0.54, ρ = 0.05, p = 0. 41.
4. DISCUSSION
⌅The
results presented in the preceding sections will be considered in terms
of their effect sizes, rather than referring only to their statistical
significance (see Cumming, 2012Cumming, G. (2012). Understanding the new statistics: Effect sizes, confidence intervals, and meta-analysis. Routledge.
,
especially chapter 2). There is a growing trend in the social sciences
to answer research questions not with a dichotomous yes or no, that is,
whether a result is statistically significant or not. Rather, the focus
of statistical interpretation is shifting to a recognition of the
magnitude of the detected effects, instead of solely considering its
statistical significance below an arbitrary p value (e.g., p < 0.05; see Cohen, 1990Cohen, J. (1990). Things I have learned (so far). American Psychologist, 45(12), 1304-1312. https://psycnet.apa.org/record/1991-11596-001?doi=1
). This statistical reform movement is gathering momentum in areas such as second language acquisition (see, e.g, Gass, Loewen, & Plonsky, 2021Gass, S., Loewen, S., & Plonsky, L. (2021). Coming of age: the past, present, and future of quantitative SLA research. Language Teaching, 54, 245-258. https://www.cambridge.org/core/journals/language-teaching/article/coming-of-age-the-past-present-and-future-of-quantitative-sla-research/B30BA387EDA5B60A07DBBBF03E4BC45C
), and it firmly encourages answering research questions as how much of an effect was found, not as whether or not there was an effect (Cumming, 2012, p. 34Cumming, G. (2012). Understanding the new statistics: Effect sizes, confidence intervals, and meta-analysis. Routledge.
).
One aspect of the statistical analyses that merits attention is the decision to use separate analyses for the native and non-native data. One motivation to do this was that, for the analysis of VOT measurement method in non-native English, the data were not normally distributed, and hence non-parametric tests were opted for. In contrast, the data for native English for the same variable were normally distributed. Thus, the analyses were split by language population, which potentially lessens the interpretation of the results. It may have been more fruitful to make a more general analysis on all the data, for example including nativeness as a predictor (i.e., native English vs. non-native English), together with the other factors and their interactions. This is a limitation of the study and future research may circumvent this methodological problem, perhaps by implementing statistical tests that are robust to violations of statistical assumptions such as normality of the data.
The first research question asked about the effect of
measurement method of MBs on VOT, that is, whether the VOT values of the
voiceless plosives differed substantially when this acoustic
characteristic was measured from the first or the last burst to the
onset of voicing. In non-native English, it was found that the
measurement method in the presence of MBs had a fair impact on VOT.
These two methods differed by about 11 ms, which in terms of VOT can be a
substantial difference, for example, when describing a voiceless
plosive as aspirated or not (e.g., Docherty, 1992Docherty, G. J. (1992). The timing of voicing in British English obstruents. Foris.
). The effect size for this finding was medium, η 2 = 0.09, which means that 9% of the variance in VOT values
was associated with the MB measurement method. For native English, it
was found that the MB measurement method had as well a medium effect
size, η 2 = 0.07. The two methods in native English differed by
almost 13 ms, which also constitutes a meaningful difference. Both
results are to some extent comparable with the findings of Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
, who found that in Western Andalusian Spanish 18%
of the variance in VOT values was associated with the measurement
method in the presence of MBs. This researcher also reported a
difference of 8 ms when the voiceless plosives were measured from the
first or last burst. In Hungarian, Gráczi and Kohári (2014)Gráczi,
T. E., & Kohári, A. (2014). Multiple bursts in Hungarian voiceless
plosives and VOT measurements. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 158-161). Cologne, Germany. /https://www.researchgate.net/profile/Anna-Kohari/publication/305635295_Multiple_bursts_in_Hungarian_voiceless_plosives_and_VOT_measurements/links/579648c508aed51475e54c81/Multiple-bursts-in-Hungarian-voiceless-plosives-and-VOT-measurements.pdf
reported on the effects of three VOT measurement
methods when MBs were present (the first burst, the most intense burst,
and the last burst), finding that these differed statistically
significantly and with medium effect sizes, similarly to the results of
the current study. It could be argued that, obviously, the two VOT
measurements would produce different results; the first measurement will
logically yield larger values than the second, in all measurements, and
it could also be reasoned that with a large enough sample size a
significant difference and an associated substantial effect size will be
found. There are, however, two problems with this reasoning. First, it
is far from clear which measurement method researchers use in their
analyses of VOT, since this is many times not reported. Thus, VOT values
described in past research might be affected by this methodological
inconsistency. Second, statistically, the effect size is not dependent
on sample size; it is derived from two parameters, the mean and the
standard deviation (for example, Cohen’s d). Thus, effect sizes are not biased by either large or small sample sizes (Plonsky & Oswald, 2014Plonsky, L., & Oswald, F. L. (2014). How big is “big”? Interpreting effect sizes in L2 research. Language Learning, 64(4), 878-912. https://doi.org/10.1111/lang.12079
).
The first research question also inquired
about the role that PoA may play in VOT values, in the presence of MBs.
The effect of PoA on VOT in non-native English was statistically
significant, with a medium effect size (η 2 = 0.06). In native English this effect was as well statistically significant and much larger, η 2 = 0.18. These findings are in line with the data reported
in previous literature, especially in the case of native English. The
post-hoc tests revealed that in non-native English, for /p/, when
measured from the first or the last burst, there was a mean difference
of almost 7 ms, with a small effect size (d = 0.22). In native English, the difference amounted to about 8 ms, in this case with a medium effect size (d = 0.44). The results for /t/ are as follows. In non-native English, the
mean difference according to measurement method was around 6 ms, and
the associated effect size was small (d = 0.26). In native
English, this plosive differed in 11.50 ms as per measurement method,
which is a sizable amount; the effect size related to this difference
was medium (d = 0.66). Lastly, /k/ yielded the largest mean
differences and associated effect sizes in both non-native and native
English; for the former, the mean difference was about 14 ms, with a
large effect size (d = 0.72), and for the latter, there was the same mean difference of around 14 ms, with an associated large effect size (d = 0.82). The effect sizes reported by Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
for the Spanish dialect he investigated are to
different degrees in line with the findings of the current study. In
this research, /p/ presented a mean difference of 6 ms according to
measurement method, with a large effect size, d = 0.78; the mean difference for /t/ was 5 ms, with a medium effect size, d = 0.65; and for /k/ the mean difference was 13.51 ms, with a very large effect size, d = 1.75. Thus, the data for this Spanish variety are, to a certain
extent, comparable to the findings for non-native English reported in
the present study, on account of the mean differences found according to
the VOT measurement method in the presence of MBs. These cumulative
findings therefore suggest that the measurement method plays a
significant role in the VOT values obtained, and future research on VOT
in which MBs are found should probably be aware of this important
methodological issue, as further discussed in Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
.
The role of PoA, gender, age, and speech
rate in MBs was the focus of the second research question. Regarding
PoA, in non-native English 41% of the plosives analyzed exhibited MBs,
with an associated medium effect size. This percentage is higher than in
the Spanish dialect researched by Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
, who found that 25% of the plosives presented MBs. It is also much higher than the percentage reported by Lavoie (2001)Lavoie, L.M. (2001). Consonant strength: Phonological patterns and phonetic manifestations. Routledge.
for American English, whose analysis found that only 9% of the
voiceless plosives had MBs. Further, Lavoie found that 11.5% of the
Spanish voiceless plosives she examined had MBs, a figure that is
clearly much lower than what was reported in the current study. Lastly, Gráczi and Kohári (2014)Gráczi,
T. E., & Kohári, A. (2014). Multiple bursts in Hungarian voiceless
plosives and VOT measurements. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 158-161). Cologne, Germany. /https://www.researchgate.net/profile/Anna-Kohari/publication/305635295_Multiple_bursts_in_Hungarian_voiceless_plosives_and_VOT_measurements/links/579648c508aed51475e54c81/Multiple-bursts-in-Hungarian-voiceless-plosives-and-VOT-measurements.pdf
, who quantified MBs in Hungarian, documented that
nearly 48% of the voiceless plosives realizations evidenced MBs; this
result is somewhat similar to the data reported above for non-native
English. Almost 77% of the plosives produced in native English presented
MBs (with a very large effect size) a figure that surpasses all the
previous results. The difference between non-native English and native
English in MBs yielded a statistically significant result, with a medium
effect size (Phi = 0.38).
Proceeding with the number of MBs for
the three plosives, it was found that in non-native English slightly
over a quarter of the bilabials had MBs, and that in native English the
percentage was about 34%. This result is in line with the percentage
reported for Hungarian by Gráczi and Kohári (2014)Gráczi,
T. E., & Kohári, A. (2014). Multiple bursts in Hungarian voiceless
plosives and VOT measurements. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 158-161). Cologne, Germany. /https://www.researchgate.net/profile/Anna-Kohari/publication/305635295_Multiple_bursts_in_Hungarian_voiceless_plosives_and_VOT_measurements/links/579648c508aed51475e54c81/Multiple-bursts-in-Hungarian-voiceless-plosives-and-VOT-measurements.pdf
, 27.5%, but very different from the data presented for English by Lavoie (2001)Lavoie, L.M. (2001). Consonant strength: Phonological patterns and phonetic manifestations. Routledge.
, 5%, and for Spanish by the same author, 0%. Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
found that in Spanish only about 10% of the
bilabials had MBs. The next plosive, /t/, presented MBs in a quarter of
its realizations in non-native English, and in native English about 16%
of the productions of /t/ had MBs. Gráczi and Kohári (2014)Gráczi,
T. E., & Kohári, A. (2014). Multiple bursts in Hungarian voiceless
plosives and VOT measurements. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 158-161). Cologne, Germany. /https://www.researchgate.net/profile/Anna-Kohari/publication/305635295_Multiple_bursts_in_Hungarian_voiceless_plosives_and_VOT_measurements/links/579648c508aed51475e54c81/Multiple-bursts-in-Hungarian-voiceless-plosives-and-VOT-measurements.pdf
reported many more MBs for /t/ (45%), and Lavoie (2001)Lavoie, L.M. (2001). Consonant strength: Phonological patterns and phonetic manifestations. Routledge.
found 0.8% of MBs for this consonant in English, whereas she reported 0% MBs for /t/ in her Spanish data. Also for Spanish, Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
found that about 15% of /t/ productions presented
MBs. Finally, in non-native English in the current study /k/ had MBs in
nearly 78% of the realizations, and around 67% of the /k/ productions
had MBs in native English. This finding is overall in agreement with the
data obtained by Gráczi and Kohári (2014)Gráczi,
T. E., & Kohári, A. (2014). Multiple bursts in Hungarian voiceless
plosives and VOT measurements. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 158-161). Cologne, Germany. /https://www.researchgate.net/profile/Anna-Kohari/publication/305635295_Multiple_bursts_in_Hungarian_voiceless_plosives_and_VOT_measurements/links/579648c508aed51475e54c81/Multiple-bursts-in-Hungarian-voiceless-plosives-and-VOT-measurements.pdf
, but very different from the 21% of MBs for /k/ reported by Lavoie (2001)Lavoie, L.M. (2001). Consonant strength: Phonological patterns and phonetic manifestations. Routledge.
for English. In Spanish, Lavoie found that 32% of the /k/ productions
presented MBs, which is coincident with the percentage found by Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
. The present study found that non-native English
and native English did not vary in the mean number of bursts, which for
both varieties was M = 2.40, with a trivial effect size.
Addressing
now the number of bursts by PoA, non-native English /p/ had the
majority of bursts in the 2-burst rank, as did this consonant for native
English. /t/ in non-native English had almost all of the MBs also in
the 2-burst category, whereas native English was more spread between the
2- (72%) and 3-burst (28%) ranks; it is remarkable that this consonant
did not show any MBs in the 4- and 5-burst categories for either English
variety. /k/ had MBs across the entire series of ranks, and with the
same percentages for both non-native and native English. Non-native
English and native English differed in the occurrence of MBs by PoA in
the bilabials, with a small effect size, a result that also applied to
the alveolars; for the velars, however, the difference was negligible,
as per the effect size observed. The results reported by Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
for Spanish and by Gráczi and Kohári (2014)Gráczi,
T. E., & Kohári, A. (2014). Multiple bursts in Hungarian voiceless
plosives and VOT measurements. In S. Fuchs, M. Grice, A. Hermes, L.
Lancia, & D. Mücke (Eds.), Proceedings of the 10th International Seminar on Speech Production (ISSP) (pp. 158-161). Cologne, Germany. /https://www.researchgate.net/profile/Anna-Kohari/publication/305635295_Multiple_bursts_in_Hungarian_voiceless_plosives_and_VOT_measurements/links/579648c508aed51475e54c81/Multiple-bursts-in-Hungarian-voiceless-plosives-and-VOT-measurements.pdf
for Hungarian are to a great extent comparable to
the data of the current study. Thus, this seems to corroborate a
general tendency of the voiceless plosives that exhibit MBs. The PoA of
the plosives had a large effect on the number of MBs both in non-native
English and native English, explaining 23% and 15% of the variance
respectively; this concurs with the data reported by Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
. A related question was whether the L1 had an
effect on the number of MBs; it was found that the difference in mean
bursts by L1 was not statistically significant and the corresponding
effect size was small (only 2% of the variance in MBs could be ascribed
to the L1). None of the pairwise comparisons yielded significant
differences in the mean number of bursts among the twelve L1s. This
result is perhaps unexpected, since the various L1s analyzed present
very different VOT patterns in their native speech. For example, Russian
voiceless plosives are not aspirated (Yanushevskaya & Bunčić, 2015Yanushevskaya, I., & Bunčić, D. (2015). Russian. Journal of the International Phonetic Association, 45(2), 221-228. https://doi.org/10.1017/S0025100314000395
), but Hindi has a phonological contrast between voiceless unaspirated and voiceless aspirated plosives (Ladefoged & Johnson, 2015Ladefoged, P., & Johnson, K. (2015). A course in phonetics. 7th ed. Cengage Learning
).
An additional factor that may play a role in MBs is speaker gender. In line with Plauché (2001)Plauché,
M. (2001). Acoustic cues in the directionality of stop consonant
confusions [Doctoral dissertation]. University of California, Berkeley,
United States of America. https://escholarship.org/uc/item/8hz6k4c2
and Barrera-Pardo (2022)Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
, the current study did not find an association
between gender and MBs. Speech rate, as in previous studies (but
partially contrary to Barrera-Pardo, 2022Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
), was not found to have an effect on MBs in
either non-native English or native English. Lastly, in non-native
English, the factor age had a small effect on the number of bursts (ρ =
0.10,), and it played essentially no role in native English. Parveen and Goberman (2012)Parveen, S., & Goberman, A.M. (2012). Presence of stop bursts and multiple bursts in younger and older adults. Asia Pacific Journal of Speech, Language, and Hearing, 15(4), 265-275. https://www.tandfonline.com/doi/abs/10.1179/136132812804731811
also reported a lack of association between age and MBs.
Finally,
this investigation of MBs may be relevant in a number of speech
research areas. MBs have been repeatedly reported in pathological speech
when measuring VOT (e.g., Fischer & Goberman, 2010Fischer, E., & Goberman, A. M. (2010). Voice onset time in Parkinson disease. Journal of Communication Disorders, 43(1), 21-34. DOI: 10.1016/j.jcomdis.2009.07.004
; Kopkalli-Yavuz, Mavis, & Akyldiz, 2011Kopkalli-Yavuz, H., Mavis, I., & Akyldiz, D. (2011). Analysis of VOT in Turkish speakers with aphasia. Clinical Linguistics & Phonetics, 25(4), 287-301. DOI: 10.3109/02699206.2010.529541
; Novotný et al., 2015Novotný, M., Pospíšil, J, Čmejla, R., & Rusz, J. (2015). Automatic detection of voice onset time in dysarthric speech. In 2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) (pp. 4340-4344).IEEE. DOI:10.1109/ICASSP.2015.7178790
). Lacking full control of their motor
capabilities, these speakers tend to evidence a substantially higher
number of MBs than speakers without speech disorders, as reported in
past studies. The cumulative results of the current study, together with
those of previous research (Barrera-Pardo, 2022Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
), suggest that MBs are present in nonpathological
populations to a larger extent than what may have been normally
assumed. VOT has also been extensively explored in second language (L2)
perception (Major, 2001Major, R. C. (2001). Foreign accent: The ontogeny and phylogeny of second language phonology. Lawrence Erlbaum.
) and production (Zampini, 2008Zampini, M. (2008). L2 speech production research. In J. H. E. & M. Zampini (Eds.), Phonology and second language acquisition (pp. 219-249). John Benjamins.
).
However, to date, the presence of MBs and the complications that may
arise when measuring the VOT of L2 speakers’ productions remains an
uncharted area. The current study suggests that in non-native English,
as reported for the twelve L1s explored, the presence of MBs needs to be
considered when analyzing VOT. Systems of automatic detection of VOT
(e.g., Kazemzadeh et al., 2006Kazemzadeh,
A., Tepperman, J., Silva, J., You, H., Lee, S., Alwan, A., &
Narayanan, S. (2006). Automatic detection of voice onset time for use in
pronunciation assessment. INTERSPEECH 2006, n.p.
) should probably take into account the potential occurrence of MBs in the data they probe.
5. CONCLUSION
⌅Systematically
analyzing and quantifying MBs has been rarely addressed in the
literature. The current study aimed at discerning the role of MBs in VOT
measurement and the potential role of the factors PoA, gender, speech
rate, and age in two varieties, non-native English, with data from
twelve L1s, and native English. Expanding on previous studies, it was
found that the VOT measurement method in the presence of MBs had a
substantial effect in both varieties, and it is therefore concluded that
researchers who embark on VOT measurement of voiceless plosives take
heed of the findings reported in prior research and in the present
study. Since VOT is one of the most studied consonant features in the
phonetics literature (Whalen, DiCanio, & Dockum, 2022Whalen, D. H., DiCanio, C., & Dockum, R. (2022). Phonetic documentation in three collections: Topics and evolution. Journal of the Phonetic International Association, 52(1), 95-121. DOI: https://doi.org/10.1017/S002310030000079
), this recommendation seems all the more
pressing. The results of the present study also supported previous
research findings that clearly indicate an effect of PoA on MBs,
especially for /k/. In addition, this study quantified MBs of voiceless
plosives, something that has rarely been done in the literature: MBs are
almost routinely noted, but data of the type reported here add to our
knowledge base of this phonetic event. These data also suggest that
although there are some sizeable differences between non-native English
and native English, overall both varieties exhibited similar tendencies
when the factors of PoA, gender, age, and speech rate were subjected to
analysis. Together with previous research, these findings seem to unveil
aspects of voiceless plosives that are not language-specific. To
conclude, a number of limitations of the current study will be noted.
Data were obtained from only three words in the elicitation passage, and
future research of the type reported here should expand to more tokens,
and in different vowel contexts, considering that prior research has
suggested a potential effect for vowel height on MBs (Barrera-Pardo, 2022Barrera-Pardo, D. (2022). Measurement of the VOT of voiceless plosives: Multiple bursts in Western Andalusian Spanish. Estudios de Fonética Experimental, XXXI,81-95. https://www.ub.edu/journalofexperimentalphonetics/pdf-articles/XXXI-07-Barrera.pdf
; Yang, 2018Yang, J. (2018). Development of stop consonants in three- to six-year-old Mandarin-speaking children. Journal of Child Language, 45, 1091-1115. DOI: https://doi.org/10.1017/S030500918000090
). The current study focused on aspirated
voiceless plosives; it would be pertinent to address voiceless plosives
in unstressed positions, and examine whether they also present MBs. In
American English, Lavoie (2001)Lavoie, L.M. (2001). Consonant strength: Phonological patterns and phonetic manifestations. Routledge.
found no MBs for unstressed /p/ and /t/, and only 10% of unstressed
voiceless velars presented MBs. She analyzed voiceless plosives in both
initial (as in Tucson) and medial position (as in boutique); the present study obtained data only from three monosyllabic words (peas, toy, kids),
and it would be relevant to extend this research to multisyllabic
words. All these factors may play a role in the production of MBs. In
addition, the analysis of speech rate in the current study was
conditioned by the recorded speaking task, the elicitation passage, and
future research may avoid this limitation by carrying out a different
production task.