Content uploaded by Michelle Dana Cohn
Author content
All content in this area was uploaded by Michelle Dana Cohn on Jul 29, 2020
Content may be subject to copyright.
Does top-down information about speaker age guise influence perceptual
compensation for coarticulatory /u/-fronting?
Georgia Zellou (gzellou@ucdavis.edu)
Department of Linguistics, Phonetics Lab, UC Davis, 1 Shields Avenue
Davis, CA 95616 USA
Michelle Cohn (mdcohn@ucdavis.edu)
Department of Linguistics, Phonetics Lab, UC Davis, 1 Shields Avenue
Davis, CA 95616 USA
Aleese Block (asblock@ucdavis.edu)
Department of Linguistics, Phonetics Lab, UC Davis, 1 Shields Avenue
Davis, CA 95616 USA
Abstract
The current study explores whether the top-down influence of
speaker age guise influences patterns of compensation for
coarticulation. /u/-fronting variation in California is linked to
both phonetic and social factors: /u/ in alveolar contexts is
fronter than in bilabial contexts and /u/-fronting is more
advanced in younger speakers. We investigate whether the
apparent age of the speaker, via a guise depicting a 21-year-
old woman or a 55-year-old woman, influences whether
listeners compensate for coarticulation on /u/. Listeners
performed a paired discrimination task of /u/ with a raised F2
(fronted) in an alveolar consonant context (/sut/), compared to
non-fronted /u/ in a non-coronal context. Overall,
discrimination was more veridical for the younger guise, than
for the older guise, leading to the perception of more inherently
fronted variants for the younger talker. Results indicate that
apparent talker age may influence perception of /u/-fronting,
but not only in coarticulatory contexts.
Keywords: speech perception; u-fronting; compensation for
coarticulation; apparent speaker age
Introduction
Knowledge about the connection between social properties of
speakers and their speech patterns interacts with the sound-
to-meaning mapping (e.g., Sumner et al., 2013).
Coarticulation, the overlapping of adjacent segments in
speech, has been understudied with respect to this
phenomenon. There is work in speech production
demonstrating that amount of coarticulatory variation is
connected to regional, social, diachronic, and stylistic speech
patterns (Harrington et al., 2008; Kataoka, 2011;
Scarborough & Zellou, 2013; Scarborough et al., 2015),
suggesting that speakers can learn to use coarticulation in
socially meaningful ways. In the current study, we ask
whether listeners are sensitive to differences in expected
coarticulatory patterns across social groups and use this
information when compensating for coarticulation.
One method for exploring listeners’ knowledge about the
relationship between speaker groups and speech patterns is
by presenting listeners with the same stimuli, but varying the
speaker guise. For example, Niedzielski (1999) found that the
apparent regional status of a talker can influence vowel
categorization: participants’ task was to match tokens with
“Canadian raised” vowels (i.e., [ɑɪ] produced as [ʌɪ])
produced by a Detroit speaker to synthetic raised or canonical
vowels. Half were told the speaker was from Detroit, while
the other half were told speaker was from Canada. Listeners
classified the apparent-Canadian as (accurately) producing
the raised vowel variant; yet, they perceived the apparent-
Michigander’s vowels as reflecting the canonical standard
American English pronunciation. In other words, the same
sound was categorized differently depending on the social
information provided about the talker: the Detroit
participants reported awareness that vowel raising is a
Canadian, not a Michigan, feature and this guided their low-
level perceptual categorization of the same stimuli. Other
types of explicit social information elicit this top-down
influence on speech perception, such as photographs
depicting speakers of various ages (Hay, Warren, & Drager,
2006) and stuffed animal toys referencing dialect regions
(Hay & Drager, 2010).
Recent speech perception theories propose mechanisms
to account for the influence of social information on the
sound-to-meaning mapping. For example, Sumner et al.
(2013) suggest that spoken word recognition operates in
parallel with social representational mapping and
interactivity between these processes can modulate linguistic
comprehension. Pierrehumbert (2002) posits that linguistic
and social information are perceptually encoded together via
rich exemplars and that socially idealized properties can
weight exemplars more strongly, pulling the distributional
space for lexical representations in one direction or another;
this distribution then shapes subsequent perception of sounds
and experiences. A fuller understanding of the role social
information plays in the simultaneous mapping of sounds and
social categories is needed to inform our understanding of
linguistic representations and speech comprehension.
Compensation for coarticulation
One area that remains understudied with respect to top-
down effects of speaker social information is compensation
for coarticulation, or segmental overlap of adjacent speech
sounds. Compensation for coarticulation is a perceptual
reduction, or elimination, of context-specific acoustic
variation. For instance, a nasalized vowel in isolation is
perceived as nasal, but when the same nasalized vowel occurs
adjacent to nasal consonants (in a [m_m] frame) it is not
perceived as nasal (Kawasaki, 1986). As soon as the putative
source of coarticulation is heard, the acoustic variation is
attributed to that source as the listener decides how the speech
signal should be parsed into discrete underlying units.
Coarticulatory compensation, thus, can be seen as a useful
perceptual process since it provides listeners with ways of
adjusting to systematic variation within the speech signal and
identifying invariant units (Beddor et al., 2013; Zellou &
Dahan, 2019). At the same time, compensation for
coarticulation ascribes context-sensitive acoustic information
to its source, making veridical acoustic perception more
challenging (cf. Kawasaki, 1986). Furthermore, native-
language experience influences the degree to which a listener
compensates for coarticulatory detail present on a vowel:
native Shona speakers, who produce less extensive
coarticulation in Shona than in English, compensate less for
English vowel-to-vowel coarticulation than English speakers
(Beddor et al., 2002). In other words, listeners use their
language-specific learned coarticulatory structures to parse
the speech signal.
In the realm of speech production, coarticulation was
traditionally viewed as the invariant, physiological
connection between the speech signal and abstract phonemes
and, therefore, having no relevance to the linguistic grammar.
Yet, few studies have explored the social impact on
compensation for coarticulation. In an eye tracking
experiment, Coetzee et al. (2019) measured fixations toward
visually presented CVC–CVN(C) pairs while participants
heard the words produced by speakers of two varieties of
Afrikaans: one variety that uses greater nasal coarticulation,
and one that uses less. They found that listeners display
learning for the Afrikaans dialect with greater anticipatory
nasal coarticulation with earlier fixations. This work suggests
that social knowledge about a given speaker’s dialect can
shape our ability to extract and learn patterns from their
speech. Yet no prior work, to our knowledge, has examined
whether manipulating top-down apparent social
characteristics might impact listeners’ compensation for
coarticulation.
Examining these top-down influences can additionally
inform theories of speech perception as to how listeners
integrate social information, specifically during
compensation for coarticulation. For example, evidence of
perceptual compensation for non-linguistic stimuli and in
non-human species has been used to argue for domain-
general auditory mechanisms in speech perception (Diehl et
al., 2004); yet, aside from linguistic experience, this ‘general
approach’ does not make explicit claims about how — or
whether — other speaker-indexical information might be
integrated. One possibility is that we might not expect
listeners to show differences in perceptual compensation
based on top-down social guise, given identical stimulus
items, where listeners are relying on general auditory
mapping mechanisms. Variationist accounts of
coarticulation, on the other hand, have pointed to evidence
that coarticulatory patterns are highly variable, both across
and within speakers (e.g., Solé, 1992; Scarborough & Zellou,
2013; Zellou & Tamminga, 2014). That language-specific
patterns of perceptual compensation are linked to produced
coarticulatory extent means that phonetic representations can
be rich enough to encode coarticulatory patterns via linguistic
experience (Beddor & Krakow, 1999; Beddor et al., 2002).
Furthermore, decades of empirical phonetic research
establish that coarticulatory patterns can vary across
languages (e.g., Beddor et al., 2002), across regional varieties
of a language (Tamminga & Zellou, 2015), and across
generations of speakers within one variety (Zellou &
Tamminga, 2014; Harrington et al., 2008). In other words,
there is evidence to support the view that coarticulatory
structures are encoded in the grammatical system of a
language and socially learned.
Vowel variation is linked to both social groups (Labov et
al., 2006) and context-specific influences (Farnetani &
Recasens, 1997). Variation in high back vowel fronting in
California English, in particular, has been correlated with
both social and phonetic factors. For one, the California
Vowel Shift (CVS) is an ongoing sociolinguistic sound
change; the most salient aspect of this shift includes fronting
of the back rounded vowels. California /u/-fronting is most
advanced in younger speakers’ productions, suggesting that
there are categorically different /u/ targets across generations
(Hall-Lew, 2011). Also, /u/ before alveolar consonants is
fronter than in bilabial contexts, due to coarticulation
(Kataoka, 2011). Because /u/-fronting is linked to both social
and coarticulatory factors, there can be ambiguity for
listeners as to the source of a higher F2. While these two
studies did not find an interaction between age and context
on /u/-fronting in California speakers’ productions (Hall-
Lew, 2011; Kataoka, 2011), it is possible that listeners may
still differentially apply social knowledge to these
productions (here, resulting in differences in compensation
for coarticulation). To test this question in the present study,
we hold the acoustic information constant and vary the top-
down guise (as a ‘younger’ or ‘older’ speaker).
Current study
In the current study, we explore whether the mapping of
coarticulatory variation to linguistic structure is guided by a
listener’s expectations about a speaker’s coarticulatory
patterns based on apparent speaker age. In particular, we test
whether a guise of an apparent older versus younger adult
influences Californian listeners’ compensation for
coarticulation for alveolar codas on /u/-fronting. As
mentioned earlier, California /u/-fronting is most advanced in
younger speakers, than older speakers (Hall-Lew, 2011).
And, independently, /u/ before alveolar consonants is fronter
due to coarticulation (Kataoka, 2011). It is plausible that
listeners have formed social indices for different
coarticulatory patterns based on experience with speaker age
groups whose coarticulatory distributions vary (Harrington et
al., 2008). Thus, we hypothesize that listeners use these
representations to compensate differently depending on
explicit social information provided about the talker. In
particular, listeners might expect a younger speaker to have
phonologized /u/-fronting, whereas they might expect older
speakers’ fronted /u/ to be the result of coarticulatory
influences from an anterior consonant. Therefore, we predict
listeners will be less likely to attribute a higher F2 to the
articulatory effects of subsequent alveolar consonant (e.g.
/sut/ “suit”) when told the speaker is a younger adult,
compared to an apparent older adult speaker.
To test compensation for coarticulation, we used a paired
vowel discrimination paradigm, which has been used in prior
work to examine perceptual compensation for coarticulation
(Beddor & Krakow, 1999). In a paired discrimination task,
listeners hear two pairs of words containing fronted or backed
vowels in alveolar and bilabial consonant contexts.
Participants’ task is to indicate which pair contains vowels
that sound the most different. We predict that the apparent
age of the speaker will influence whether listeners
compensate for coarticulation on /u/, leading to the veridical
perception of more fronted variants for younger talkers.
Another potential outcome is that social information does not
influence the perception of coarticulation and there will be no
difference in perceptual compensation behavior as a function
of speaker age guise.
Methods
Participants
85 native English-speaking undergraduates (60 females, 25
males; mean age = 21.1 ± 2.3 years old) were recruited from
the UC Davis Psychology subject pool. All participants
indicated that they were from California. They participated in
the experiment on online platform (Qualtrics) and received
course credit for their participation. Sample size was
calculated based on a power analysis in G*Power (Faul et al.,
2007) assuming power of .95, 3 predictors, and a small-to-
medium effect size.
Stimuli
Stimuli materials were created by eliciting ‘soup’ [sup] (non-
coronal) and ‘suit’ [sut] (coronal) from a native Californian
female. After vowels were extracted, F2 was manipulated +/-
80 Hz to create fronted and backed versions of each vowel
using the VocalToolkit package (Corretge, 2012) in Praat
(Boersma & Weenink, 1996). For all vowels, f0 was
controlled to have a smoothed falling f0 contour (from 225
Hz to 200 Hz, decreasing linearly from the start to the end of
the vowel). Vowel durations were also normalized to 150 ms,
and stimuli were normalized in intensity (50 dB). The vowels
were then spliced into the original word context.
Procedure
Participants completed a 4-interval forced-choice (4IAX)
paired discrimination paradigm (Beddor & Krakow, 1999) to
assess their ability to discriminate between fronted and
backed versions of /u/ in coronal and non-coronal
consonantal contexts. For each trial, two pairs of stimuli were
presented to a listener: one pair contained acoustically
identical vowels and the other pair contained acoustically
different vowels (i.e., fronted vs. backed). Listeners were
instructed to decide which pair contained different sounding
vowels (two possible responses: first or second
pair). Participants completed two types of trials (randomly
presented), which varied the consonantal context: ‘same
context’ (control) trials and 'different context’ (test) trials.
Same context (control) trials contained identical
consonant contexts across pairs, all non-coronal [sup] or
coronal [sut]. In each set of stimuli, one pair contained
vowels differing in backing, while the others were
acoustically identical (both fronted or backed). For example:
Pair 1 [supBac k] [supBack ] vs. Pair 2 [supBack] [supFront] (bolded pair
contains acoustically distinct vowels). Order of differing
vowels within and across pairs was counterbalanced across
trials. We expect veridical acoustic vowel perception to be
the highest in control trials, because when consonantal
context is identical, compensation should equally attribute (or
equally not attribute) acoustic variation to the source across
vowels (Beddor et al., 2002; Zellou et al., 2020).
Different context (test) trials contained varying coda
contexts: each pair of words included a non-coronal [sup] and
coronal [sut] (order of [sut]/[sup] counterbalanced). One pair
within the trial had acoustically identical vowels (e.g., both
backed or both fronted); the other pair was had different
vowels always in the direction of interest, with the fronted /u/
in a coronal context: [sutFront], [supBack]. For example: Pair 1
[sutFront] [supBack] vs. Pair 2 [sutFr on t ] [supFront] (bolded pair
contains acoustically distinct vowels). Ordering within and
across vowel pairs was counterbalanced across trials. If
compensation occurs, listeners should hear the fronted vowel
in the alveolar consonant context as the ‘same’ as the backed
vowel, reflecting less veridical acoustic perception. Thus, the
vowel in [sutFront] might sound more similar to the vowel in
[supBack] if compensation occurs.
Subjects heard the same set of stimuli across two blocks
varying in apparent age of the speaker: one block presented a
younger speaker guise, the other, an older-speaker guise
(Figure 1). Participants were given both the apparent name
and age of the speaker (e.g. “You will hear Linda, a 55-year-
old woman, producing two pairs of words”). Participants’
exposure to the older and younger guises was
counterbalanced across subjects (e.g., “Linda” first,
“Madison” second).
In total, participants completed 32 trials (randomly
presented across test and control conditions). As the
experiments was conducted online, we included listening
four comprehension questions interspersed throughout the
experiment (e.g., “Who is older, Linda or Madison?”);
participants’ data was retained only if they answered all four
questions correctly (n=85).
Figure 1: Stock images used for the apparent age guises.
Older age guise: (panel A) 55-year-old “Linda” and Younger
age guise: (panel B) 21-year-old “Madison”.
Predictions
Overall, we expect a main effect of Context on listeners’
accuracy in identifying acoustically distinct vowels.
Listeners’ performance should be highest in the Same
Context condition, relative to the Different Context
conditions, where compensation for coarticulation from the
differing coda consonant will make veridical vowel
perception more challenging.
We also critically expect an interaction between Context
and Age Guise: if listeners’ expectations about age-related
differences in produced coarticulation guide their perceptual
compensation, we predict different patterns of veridical
perception in Different word context conditions. In
particular, we expect less compensation, i.e., more veridical
perception, for the younger age guise. Therefore, we predict
that listeners will be more accurate in identifying acoustically
distinct vowels in different-word pairs when given the
younger age guise, relative to when these trials are presented
with the older age guise.
Statistical analyses
We coded listeners’ responses as binomial data: if they
selected the trial with acoustically different vowels (e.g., [sut
Front] [sut Back], [sut Front ] [sup Back], etc.) (=1) or not (=0). We
analyzed these responses with a mixed effects logistic
regression (lme4 R package; Bates et al., 2015). Main effects
included Age Guise (Older, Younger), Consonantal Context
(2 levels: ‘Same context’ (i.e., control), 'Different context’
(i.e., test)), and their interaction. Random effects included by-
Subject random intercepts and by-Subject random slopes for
Guise and Consonantal Context (and their interaction).
Contrasts were sum coded. (lmer syntax: Response ~ Guise *
Context + (1 + Guise*Context | Subject).)
Results
Figure 2 shows the proportion of trials where participants
discriminated the acoustically distinct vowels. The model
output for the logistic regression is provided in Table 1. As
seen in Figure 2, higher values indicate more acoustic (i.e.,
more veridical) discrimination. First, we observed a main
effect of Consonant Context: participants showed more
veridical vowel perception when the differing vowels
occurred in the same word context (e.g., Pair 1 [supBack]
[supBack] vs. Pair 2 [supBack] [supFront]), relative to when they
occurred in different contexts. For the different-context
condition (right panel), mean values closer to chance
performance (0.50) indicate greater compensation for
coarticulation, while higher values indicate greater veridical
vowel perception (indicating failure to compensate fully).
There was also a main effect of Age Guise: vowel
discrimination in the older guise (i.e., “Linda”) was lower
than for the younger guise (i.e., “Madison”), indicating
greater overall veridical vowel perception. No interaction
between Consonant Context and Age Guise was observed.
Figure 2: Mean proportion of acoustically distinct vowels
identified (error bars show standard error) by Age Guise
(Younger, Older) and Consonant Context (Same word or
Different words). Chance performance (0.50) is indicated
with a dotted line.
Table 1. Model Output.
Coef.
SE
z
p
(Intercept)
0.46
0.05
8.59
<0.001***
Age Guise(older)
-0.09
0.04
-2.19
0.03 *
ConsContext(diff)
-0.28
0.04
-6.74
<0.001***
Age(older)*
ConsContext(diff)
0.02
0.04
0.57
0.57
Num. observations = 2,752, Num. subs = 85
Discussion
The current study examined top-down effects of apparent
speaker age (either younger or older adult) on university-aged
Californians’ social associations of fronted /u/ in the context
of alveolar codas via perceptual compensation for
coarticulation. Listeners discriminated /u/ vowels in the word
“suit” [sut] with differing F2 values (fronter or backer) in
word pairs with same (all “suit”) or varying consonantal
contexts (“suit” vs. “soup”). Overall, the consonantal context
had an effect on patterns of perceptual compensation for
coarticulation, whereby identical consonant contexts lead to
more veridical vowel perception, relative to when vowels
occurred in differing consonant contexts. Varying consonant
context across word pairs in a trial makes veridical acoustic
vowel perception more difficult due to coarticulatory
compensation: a raised F2 on /u/ adjacent to an alveolar
consonant might be factored out, making that vowel sound
more similar to a backed /u/ in another context. Listeners’
above-chance performance in vowel discrimination for
different-word contexts reflects partial compensation, in
general, replicating the phenomenon of a failure to fully
compensate for coarticulation that has been observed across
numerous studies (Beddor & Krakow, 1999; Beddor et al.,
2002; Zellou, 2017).
Additionally, we observed differences in overall vowel
discrimination performance based on the apparent age guise
of the speaker. While the stimuli were produced by a
California native in her 20s, participants were given two
different age guises: in one block, they were given an image
of the speaker depicting a woman in her 20s, in the other
block, they were given an image of the speaker depicting a
woman in her 50s. We observed differences according to age
guise: listeners displayed more veridical perception of
acoustic differences in /u/ for the apparent young adult
speaker guise, relative to the apparent older adult speaker
guise. We can interpret our finding that listeners displayed
less veridical vowel perception for the older speaker guise,
than when they were given the younger speaker guise, as
reflecting the effect of social information on distributions of
experienced vowel patterns, which subsequently guide
patterns of acoustic vowel perception (cf. Walker & Hay,
2011). The younger speaker guise ostensibly recruited
activation of the pronunciation features associated with this
accent, which included more advanced and phonologized /u/-
fronting overall (Hall-Lew, 2011). The expectation for
phonologization of /u/-fronting in this younger adult speaker
guise would lead listeners to attribute more of the raised F2
(fronting) to the vowel. On the other hand, the older adult
speaker guise lead to the expectation that /u/-fronting was less
phonologized. So, listeners were less accurate in identifying
the veridical signal, with a fronted /u/, given that top-down
expectation. The current findings are in line with Ha y,
Warren, and Drager (2006), who found that apparent-speaker
age and socio-economic status of speaker (signaled by
photographs of people in various guises), influence how New
Zealand listeners classify “near” and “square” vowels.
Participants made more errors when viewing the younger
guise, assuming it was a merged speaker, while fewer errors
were made while viewing the older guise, indicating that they
expected this speaker to be non-merged. In the current study,
as in Hay et al., we observed that listeners given different
social information about acoustically identical stimuli
displayed evidence of different phonetic and phonological
interpretations of those sounds. In other words, we find
further support that social knowledge can influence how
listeners perceive variation.
However, we do not find that social knowledge influences
patterns of compensation for coarticulation, as we predicted.
Crucially, we did not observe an interaction between Context
and Guise. While overall vowel perception was more
accurate for the younger guise, listeners did not display show
even higher performance in different-word contexts (relative
to the same-word context) for this guise. In other words,
listeners did not display differences in perceptual
compensation based on age guise. There are several
possibilities for this finding. For one, Hall-Lew (2011) did
not find differences across ages in patterns of /u/-fronting
based on consonant context. Therefore, it is possible that
listeners are attending to variation in coarticulation across
social groups, but this is not at play for these social groups
for this acoustic feature. Future work looking at both
production and perception in variation of coarticulation, in
tandem, can identify social factors that might be relevant to
listeners’ expectations about coarticulatory patterns.
Additionally, all of our stimuli contained an initial coronal
consonant (soup, suit), which may have triggered
compensation across the board, weakening any potential
interaction effects.
Furthermore, as previously mentioned, the stimuli were
produced by a speaker in her 20s. Thus, the older speaker
guise was mismatching in apparent and real voice age,
whereas the younger speaker guise was not. The mismatch
could have also led to the decrease in performance for the
older speaker guise. Moreover, participants were also
university-aged and may have more experience with the
speech patterns of younger speakers, which could explain
their higher performance for the younger guise. This is in line
with Niedzielski (1999): listeners displayed more veridical
perception of their social out-group, relative to their social in-
group). Future work crossing an older voice with younger and
older speaker guise could address these confounds.
Overall, the current results extend previous work on
sociophonetic variation in perception by examining how
social information influences listeners’ vowel perception
(Niedzielski, 1999) and perceptual evaluation of
coarticulation (cf. Coetzee et al., 2019). Perception of fine-
grained acoustic vowel patterns is susceptible to the influence
of apparent-speaker guise. It is still an open question of how
coarticulatory detail is influenced by top-down knowledge.
Nevertheless, future investigations and discussions of how
social knowledge affects the perception of phonetic variation
should explore coarticulatory and compensatory facts, as
well.
Finally, we can speculate about the implications of the
current findings for sound change. The influence of social
factors on speech perception and how they might interact
with linguistic change is beginning to be explored. In a set of
studies, Warren (2005) investigated the ongoing merger of
the vowels in “near” and “square” in New Zealand English.
For example, older speakers produce “square” raising only in
contexts where the phonetic environment would make that
natural, while younger speakers exhibit “square” raising in all
contexts, suggesting that this vowel change has been fully
reanalyzed for younger speakers (Warren, 2005).
These different interpretations of the ‘same sound’ (i.e.,
phoneme) mean that listeners might have differences in how
the experience is encoded in linguistic memory based on the
social information in that context (Pierrehumbert, 2002;
Sumner et al., 2013). Both Hay et al. (2006) and findings
from the current study suggest that exploring the role of
social information in the perception of linguistic variation has
important implications for understanding sound change. The
phenomenon of different apparent social characteristics
yielding different perceptual experiences can be a starting
point for understanding the conditions under which sound
change might occur. Ultimately, the current study indicates
that looking at how the interaction of how coarticulation and
sociolinguistic knowledge influences speech perception is a
promising scientific area of research and opens many
possible directions for future work.
References
Bates, D., Maechler, M., Bolker, B., Walker, S., Christensen, R.
H. B., Singmann, H., ... & Bolker, M. B. (2015). Package
‘lme4’. Convergence, 12(1), 2.
Beddor, P. S., & Krakow, R. A. (1999). Perception of
coarticulatory nasalization by speakers of English and Thai:
Evidence for partial compensation. The Journal of the
Acoustical Society of America, 106(5), 2868-2887.
Beddor, P. S., Harnsberger, J. D., & Lindemann, S. (2002).
Language-specific patterns of vowel-to-vowel coarticulation:
Acoustic structures and their perceptual correlates. Journal of
Phonetics, 30(4), 591-627.
Beddor, P. S., McGowan, K. B., Boland, J. E., Coetzee, A. W.,
& Brasher, A. (2013). The time course of perception of
coarticulation. The Journal of the Acoustical Society of
America, 133(4), 2350-2366.
Boersma, P. P. G., & Weenink, D. J. M. (1996). Praat: Doing
Phonetics by Computer: Version 3.4. Instituut voor
Fonetische Wetenschappen.
Coetzee, A. W., Beddor, P. S., Styler, W., Tobin, S., Bekker, I.,
& Wissing, D. (2019). Producing and perceiving socially
indexed coarticulation in Afrikaans. Proceedings of ICPhS.
Corretge, R. (2012). Praat vocal toolkit. Barcelona, Spain:
Praat. Retrieved from http://praatvocaltoolkit. com.
Diehl, R. L., Lotto, A. J., & Holt, L. L. (2004). Speech
perception. Annu. Rev. Psychol., 55, 149-179.
Elman, J. L., & McClelland, J. L. (1988). Cognitive penetration
of the mechanisms of perception: Compensation for
coarticulation of lexically restored phonemes. Journal of
Memory and Language, 27(2), 143-165.
Farnetani, E., & Recasens, D. (1997). Coarticulation and
connected speech processes. The handbook of phonetic
sciences, 371-404.
Faul, F., Erdfelder, E., Lang, A. G., & Buchner, A. (2007). G*
Power 3: A flexible statistical power analysis program for the
social, behavioral, and biomedical sciences. Behavior
research methods, 39(2), 175-191.
Hall-Lew, L. (2011, August). The Completion of a Sound
Change in California English. Proceedings of ICPhS (pp.
807-810).
Harrington, J., Kleber, F., & Reubold, U. (2008). Compensation
for coarticulation, /u/-fronting, and sound change in standard
southern British: An acoustic and perceptual study. The
Journal of the Acoustical Society of America, 123(5), 2825-
2835.
Hay, J., Warren, P., & Drager, K. (2006). Factors influencing
speech perception in the context of a merger-in-progress.
Journal of Phonetics, 34(4), 458-484.
Hay, J. & Drager, K. (2010). Stuffed toys and speech
perception. Linguistics, 48(4), pp. 865-892.
Johnson, K., Strand, E. A., & D'Imperio, M. (1999). Auditory–
visual integration of talker gender in vowel perception.
Journal of phonetics, 27(4), 359-384.
Kataoka, R. (2011). Phonetic and cognitive bases of sound
change (Doctoral dissertation). UC, Berkeley.
Kawasaki, H. (1986). Phonetic explanation for phonological
universals: The case of distinctive vowel nasalization. In. JJ
Ohala, & Jaeger, JJ (Eds.), Experimental phonology (pp. 239-
252).
Labov, W., Ash, S., & Boberg, C. (2006). Atlas of North
American English: Phonetics. Phonology And Sound
Change, Mouton de Gruyter.
Niedzielski, N. (1999). The effect of social information on the
perception of sociolinguistic variables. Journal of Language
and Social Psychology, 18(1), 62-85.
Ohala, J. J. (1993). Coarticulation and phonology. Language
and speech, 36(2-3), 155-170.
Pierrehumbert, J. (2002). Word-specific phonetics. Laboratory
Phonology, 7.
Scarborough, R., & Zellou, G. (2013). Clarity in
communication: “Clear” speech authenticity and lexical
neighborhood density effects in speech production and
perception. The Journal of the Acoustical Society of America,
134(5), 3793-3807.
Scarborough, R., Zellou, G., Mirzayan, A., & Rood, D. S.
(2015). Phonetic and phonological patterns of nasality in
Lakota vowels. Journal of the International Phonetic
Association, 45(3), 289-309.
Solé, Maria-Josep. "Phonetic and phonological processes: The
case of nasalization." Language and speech 35.1-2 (1992):
29-43.
Strand, E. A. (1999). Uncovering the role of gender stereotypes
in speech perception. Journal of Language and Social
Psychology, 18(1), 86-100.
Sumner, M., Kim, S. K., King, E., & McGowan, K. B. (2014).
The socially weighted encoding of spoken words: A dual-
route approach to speech perception. Frontiers in
Psychology, 4, 1015.
Tamminga, M., & Zellou, G. (2015). Cross-dialectal
differences in nasal coarticulation in American English.
In ICPhS.
Walker, A., & Hay, J. (2011). Congruence between ‘word age’
and ‘voice age’ facilitates lexical access. Laboratory
Phonology, 2(1), 219-237.
Warren, P. (2005). Patterns of late rising in New Zealand
English: Intonational variation or intonational change?.
Language Variation and Change, 17(2), 209-230.
Zellou, G. (2017). Individual differences in the production of
nasal coarticulation and perceptual compensation. Journal of
Phonetics, 61, 13-29.
Zellou, G., & Tamminga, M. (2014). Nasal coarticulation
changes over time in Philadelphia English. Journal of
Phonetics, 47, 18-35.
Zellou, G., & Dahan, D. (2019). Listeners maintain
phonological uncertainty over time and across words: The
case of vowel nasality in English. Journal of Phonetics, 76,
100910.
Zellou, G., Barreda, S., & Ferenc Segedin, B. (2020). Partial
perceptual compensation for nasal coarticulation is robust to
fundamental frequency variation. The Journal of the
Acoustical Society of America, 147(3), EL271-EL276.
