mark antoniou coc final

8/14/2019 Mark Antoniou COC Final

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Effects of linguistic context on bilingual speech production and perception

Confirmation of Candidature Proposal

Mark Antoniou

Student ID: 11018517

Supervisor: Professor Catherine T. Best

MARCS Auditory Laboratories

University of Western Sydney


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Table of Contents

1. Overview 4

2. Theories of bilingualism 4

2.1 The Bilinguals Language Modes 5

2.2 The Inhibitory Control model 6

2.3 Modeling phonological and phonetic abilities of bilinguals 6

3. Extending theories of cross-language speech production and perception to

bilinguals 7

3.1 The Speech Learning Model 8

3.2 The Perceptual Assimilation Model 11

3.3 PAM-L2 16

4. Bilingual speech perception and production research 17

4.1 The bilingual as a constantly changing perceiver-producer 21

4.2 Manipulating the linguistic context in bilingual research 22

5. The proposed research 30

5.1 Target languages 31

5.1.1 Australian English phonology 31

5.1.2 Greek phonology 33

5.1.3 Xhosa Phonology 36

5.2 Rationale 37

5.3 The Perceptual Assimilation Model of Early Bilinguals (PAM-EB) 38

6. Experiments: Investigating the effects of language of presentation on bilingualspeech production and perception 40

6.1 Ethics approval 40

6.2 Experiment 1: Production of Greek and AusE stop voicing: /p, t, k/ vs. /b, d, g/ 40

6.2.1 Aim 41

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6.2.2 Study design 41

6.2.3 Predictions 43

6.2.4 Participants and recruitment 45

6.3 Experiments 2A-2C Perception of Greek and AusE stop voicing distinctions 45

6.3.1 Aims 46

6.3.2 Study design 46

6.3.3 Experiment 2A Word-initial position CV 47

6.3.4 Experiment 2B Word-medial position VCV 48

6.3.5 Experiment 2C Word-medial position VCV 49


6.4 Study 3 Perception of nonnative Xhosa bilabial stop distinctions 50

6.4.1 Aims 51

6.4.2 Study Design 51

6.4.3 Predictions 51


7. Anticipated impact 53

8. Timeline 55

9. References 57

Appendix A. Language background information sheet 63

Appendix B. 67

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Linguistic context and bilingual speech

1. Overview

The present proposal will investigate the effects of linguistic context on the production

and perception of stop consonants by Greek-Australian English early sequential

bilinguals. Contextual effects have been addressed in theories of bilingual word selection,

code switching, and other aspects of language use, but not by theories of phonetics and

phonology, which address the system of spoken consonants, vowels, and other sound

patterns used by a language. Moreover, only a small number of cross-language studies

have investigated the influence that linguistic context can exert on bilingual speech

perception and production. A new theoretical framework will be presented that combines

the principles of existing theories of bilingual language selection with those of cross-

language speech performance, to account for effects of linguistic context on speech

production and perception in bilinguals. Within this approach, the systematic

manipulation of linguistic context within the laboratory will be referred to as the

language of presentation.

2. Theories of bilingualism

Theoretical models of bilingualism have described language modes,language activation,

and lexical inhibition to account for variability in the performance of bilinguals in their

two languages. Note that these models focus mainly on lexical (knowledge of and mental

access of words) and/or grammatical tasks, rather than specifically on the bilinguals

phonological system.

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2.1 The Bilinguals Language Modes

Grosjeans (1989; 1998; 2001) Language Mode framework postulates that at any time,

bilinguals are in language modes that correspond to points on a monolingual-bilingual

continuum. A language mode is a state of activation of the bilinguals languages and

language processing mechanisms (Grosjean, 2001). Bilinguals may be in monolingual

mode when interacting with monolingual speakers of one of their languages. In this case,

the other language is said to be deactivated (although never completely). Bilinguals will

be in bilingual mode when interacting with a bilingual speaker of the same two

languages. Under these circumstances, both languages are activated but one is used for

processing language and is therefore more active than the other. According to Grosjean,

the bilinguals language mode affects both language comprehension and performance.

Any number of factors can position a bilingual speaker or listener at a particular point on

the language mode continuum: the person(s) being spoken or listened to, the situation, the

form and content of the message, the function of the language act, and specific research

factors (does the participant know the aims of the study taking place?). Even hinting at

the bilingual abilities of a bilingual participant may put them into bilingual mode

(Grosjean, 1998). Movement along the continuum can happen at any time depending on

the factors mentioned above, usually unconsciously, smoothly and effortlessly. This may

be akin to a monolinguals automatic, smooth change of speech style or register based on

changes in context and/or interlocutor, e.g., child-directed speaking register versus adult-

directed register.

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2.2 The Inhibitory Control model

While Grosjeans Language Modes provide a framework for examining bilingual

performance across a range of linguistic tasks, the Inhibitory Control model (Green,

1998) attempts to explain how bilinguals are able to select the correct word (i.e., lexical

item) in the correct language. The Inhibitory Control model assumes that the two (or

more) languages of an individual are subsets of the language system as a whole. Lexical

selection is achieved through competition between lemmas. A lemma is a lexical

representation including its semantic (meaning), syntactic (grammatical), phonological

(consonant-vowel structure), and phonetic (spoken form) properties. All lemmas are

tagged with a language label (language A or language B). A language task schema alters

the activation levels of representations within a given language system. Lemmas with

incorrect language tags are inhibited by the language task schemas. The activation of

specific lemmas requires input either from an external source (heard or read words) or

from the conceptual system, and is therefore reactive. In this way, word candidates in

both languages can be differentially inhibited top-down on the basis of language.

2.3 Modeling phonological and phonetic abilities of bilinguals

Unfortunately, the Language Mode and Inhibitory Control models are inadequate for

guiding research at the phonological and phonetic levels. They were designed to address

lexical and syntactic aspects of language use, rather than the sound structure aspects.

These models are not capable, in their current form, of putting forth any testable

predictions and hypotheses in cross-language speech perception and production. Thus,

although interesting, merely knowing that bilinguals can move between language modes

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is not yet sufficiently developed to make predictions about how the language of

presentation could influence a bilinguals perception or production of speech. The

proposed research will be the first systematic investigation of linguistic context on early

bilingual speech perception and production at the phonetic and phonological levels. In the

present research, an important distinction is made between people who are actively

acquiring a second language (L2) L2 learners and those who have acquired their

languages and achieved a level of language stability bilinguals. It is the latter group

which will serve as the focus of the proposed research. Existing theories of cross-

language speech production and perception have focused on L2 learners (Flege, 1995)

and nonnative listeners (Best, 1995), but have not addressed the performance of fluent,

stable bilinguals.

3. Extending theories of cross-language speech production and perception to

bilinguals

Cross-language speech research aims to understand how language experience influences

the perception and production of speech. Language experience shapes perception so that

information relevant to the native language is picked up from the speech stream while

other information is ignored, which in turn affects speech production. The majority of

cross-language research has focused on monolinguals. However, about two thirds of the

worlds population is estimated to be bilingual (Grosjean, 1982). Bilingual populations

present a special opportunity to test the predictions of the theoretical models of nonnative

speech perception and production as they possess more than one language.

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Bilingual research attempts to understand whether bilinguals integrate their languages or

keep their languages separate (Flege & Eefting, 1987b; Pallier, Colome & Sebastian-

Galls, 2001; Mack, 1989). Bilinguals rarely possess an equal command of both

languages. This is because each language serves different social functions. Each language

is used with different people, in different places, for different purposes (Grosjean, 1982;

1989). However, researchers have often ignored the linguistic context in which the

research has been conducted. Evidence exists that bilinguals are able to shift their

production and perception along a continuum to adjust to the linguistic context (Grosjean,

1989; 1998; 2001; Green, 1998). This implies that bilinguals are able to select language-

specific information from the speech stream and that this selectivity in attention to

phonetic details may vary depending on the linguistic context. Obviously, this ability to

shift between languages is unique to people who speak more than one language. Less

fluent people who are still acquiring their second language (L2 learners) may not be able

to shift their language mode yet, and this may contribute to their difficulties in correctly

perceiving and producing many L2 phones. If fluent bilinguals are able to shift their

perception and production of speech according to the linguistic context, then it is

necessary to provide a theoretical explanation of how this occurs and to examine what

this means for bilingual perception of phonological and phonetic information.

3.1 The Speech Learning Model

The Speech Learning Model (SLM: Flege, 1995) attempts to explain age-related

limitations on nonnative accentedness in speech production (and secondarily, in

perception). By first predicting whether first language (L1) and L2 phones will be

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differentiated, SLM makes predictions of whether L2 learners will eventually produce

specific L2 phones without an accent.

During L1 acquisition, speech perception becomes attuned to the contrastive phonetic

elements of the L1, guiding proper production of those L1 elements. It is assumed that

these speech-learning mechanisms remain intact throughout life. This does not

necessarily mean that native-like L2 production will ever be achieved, especially by late

L2 learners, because there are ongoing changes throughout life in the way that the L1 and

L2 phonetic systems interact. Fewer L2 sounds will be pronounced accurately as age of

learning, and proficiency in the L1, increases.

SLM predicts that production and perception difficulties arise from L1/L2 phonetic

similarity. L2 learners may fail to discriminate between two L2 sounds, or an L2 and L1

sound. This leads to one of the central assumptions of SLM, that many (although not all)

L2 production errors result from native versus nonnative differences in segmental

(consonant or vowel) perception. Put simply, the accuracy with which L2 segments are

perceived will limit how accurately they will be produced.

According to SLM, L2 learners possess one phonological system. This one system

contains phonological categories from both of the L2 learners languages. Cross-language

interference is assumed to be bidirectional. A foreign accent is the result of this language

interference. It is predicted that as an L2 learner approaches the phonetic norm for an L2

phone, production of the corresponding L1 phone will move away from the L1 phonetic

norm. L2 learners often begin by producing L2 words using unmodified L1 phonetic

segments, but they typically approximate L2 phonetic norms for certain L2 phonetic

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segments more closely over time as they gain experience in the L2. This may, however,

lead to an increased degree of nonnative accentedness in the L1.

SLM predicts that L2 phonetic segments and contrasts that are very different from any L1

phonetic category will come to be perceived and produced relatively accurately, whereas

L2 phonetic segments that are more similar to L1 segments will continue to be

misperceived and mispronounced. However, some L2 phones will be too similar to L1

phones for new category formation to occur. It is predicted that early L2 learners will be

more likely to establish new phonetic categories for L2 speech sounds.

Initially, learners will perceptually relate positional allophones (similar phones perceived

by native speakers as belonging to the same phonological category in that language) in

the L2 to the closest positionally defined allophone in the L1. If an L2 phone sounds

sufficiently similar to an L1 phone, it will be perceptually assimilated (equivalence

classified in Fleges original terms) into the existing L1 category. Sounds that are

perceptually linked to one another across L1 and L2 are called diaphones, and come to

resemble each other in production. Despite audible differences between the L2 phone and

the closest L1 phone, a new category may fail to be established. This is called category

assimilation and results in a merged L1/L2 phonetic category, which may be unlike that

of a monolingual speaker of either language. In this instance, a single, merged L1/L2

phonetic category will be used to produce corresponding speech sounds in the L1 and L2.

SLM would predict that discrimination of these L1 and L2 phones would be difficult, and

production would be accented. The proposed research will investigate whether Greek-

Australian English bilinguals are able to make such distinctions of stop consonants in

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their two languages, and whether they are systematically affected by the syllable position

of those stop consonants (positional allophones).

With experience, L2 learners may gradually discriminate between certain L2 sounds and

the closest L1 sound. When this occurs, a phonetic category representation may be

established for the new L2 sound that is independent of representations established

previously for L1 sounds. The likelihood of a category being formed for an L2 phone

increases with the degree of perceived dissimilarity from the closest L1 phone. If the L2

phone is very different from any L1 phonetic category, then it will not be assimilated to

any L1 phonetic category, and will establish a new, unique phonetic category. A newly

established L2 phonetic category and the nearest L1 phonetic category will shift away

from one another in the phonetic space, called phonetic category dissimilation. SLM

posits that category dissimilation occurs because L2 learners strive to maintain phonetic

contrast between all of the L1 and L2 phonetic categories in the common phonetic space.

A phonetic category established by an L2 learner for an L2 phone may be deflected away

from an L1 phone and will therefore differ from a native speakers phonetic category for

the same L2 phone.

In summary, according to SLM, some L2 phonemes will acquire their own phonetic

category while others will not, and this will have implications for both L1 and L2

perception and production. However, SLM offers no explanation as to why or how

bilingual perception or production may shift according to the linguistic context, nor even

any predictions that it will do so.

3.2 The Perceptual Assimilation Model

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Like SLM, the Perceptual Assimilation Model (PAM: Best, 1993; 1994; 1995) of

nonnative speech perception proposes that perceivers possess one phonological system.

PAM also argues that nonnative speech segments are categorised according to their

perceived similarities to, or differences from, the phonetic segments in the native

phonological system. The PAM framework is built upon direct realist principles. Direct

realism is a philosophy that posits that we know the external world directly, without

cognitive or non-cognitive mediation. Information about the world is conveyed through

informational media, such as air and light, to our perceptual systems. These informational

media are structured by distal events in the external world. For speech, the acoustic and

optical signal of the talker is structured by the gestures of their vocal tract, which are then

perceived through lawful changes in air pressure and the reflection of light. Therefore,

when we perceive speech, we directly perceive the vocal tract gestures the distal event.

The most notable difference between PAM and SLM is PAMs assumption that there is

both a phonetic (physical, gradient) and a phonological (abstract, categorical) level of

speech perception, while SLM proposes only a phonetic level. Traditionally, it has been

assumed that speech has both a physical structure and an abstract, or cognitive, structure.

However, PAM is based upon direct realist metatheoretical assumptions. How can PAM

account for these two seemingly different (physical and abstract) structures of speech?

This is made possible through the framework of articulatory phonology.

In articulatory phonology (Browman & Goldstein, 1986, 1989, 1992, 1993, 1995, 2000;

Goldstein & Browman, 1986), these seemingly different domains are the macroscopic

(phonological) and microscopic (phonetic) levels of a single, complex system. The

degree of resolution differs at these two levels. The microscopic (phonetic) level captures

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much more of the detailed articulatory properties much more detail than is needed to

distinguish words. This is the level of gradient physical details. The macroscopic

(phonological) level captures details in terms of contrastive, rule-bound functions. This

level is only concerned with the details needed to make phonemic distinctions (used to

differentiate words). This is a global level in which the structure is more abstract. The

perceptual primitives of both phonetics and phonology are articulatory gestures.

Traditionally, phonemes have been defined as sets of static features targets that do not

change over time. By defining phonemes as static feature bundles, it is difficult to explain

historical language changes, phonological patterning (the way sounds function within a

language or across languages) and coarticulation (the assimilation of the place of

articulation of one speech segment to that of an adjacent segment). In articulatory

phonology, a gesture is dynamically defined and consists of a formation and release of a

constriction in the vocal tract. By defining gestures dynamically, it is possible to link the

macroscopic and microscopic elements of speech, and explain language change and

coarticulation. A gestural constellation is a set of coordinated gestures, i.e., defined by the

phasing of gestures relative to each other. A linguistic utterance is a constellation that can

be broken down into a number of primitives (gestures) in a certain spatio-temporal

configuration. Two speech segments will contrast if the gestural constellations differ, e.g.

if a gesture is absent in one segment, if there are differences in the degree of constriction

among gestures, or if gestures are ordered or phased differently (Browman & Goldstein,

1992). Gestures are dynamic physical events that occur in space and time, and can

overlap. Overlap may occur because several gestures can be active in the vocal tract at

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any point in time. This overlap may result in microscopic (phonetic-acoustic) variations

that have been traditionally called coarticulation effects.

According to PAM, the native phonological system, as well as phonetic details even

within a phonological category influences a listeners ability to identify and

discriminate nonnative speech segments. In articulatory phonology terms, perception of

nonnative minimal contrasts (differing in only one gesture) is guided by perceived

gestural similarities and dissimilarities between nonnative phones (speech gestures

considered as physical events) and native phonological categories.

Perceivers can assimilate nonnative segments into native phonological categories, used to

distinguish words (e.g. native /b/ vs. native /p/). However, perceivers may also be

sensitive to gradient phonetic information, allowing them to perceive within-category

differences (e.g. accented vs. unaccented consonants and vowels). Nonnative segments

may be:

1) Assimilated to a native category as:(a) a good exemplar of that category;

(b) an acceptable but not ideal exemplar of that category; or

(c) a notably deviant exemplar of that category;

2) Perceived as a speech sound that does not fit into any single existing nativecategory; or

3) Heard as a non-speech sound, e.g. a cork popping.

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When a nonnative listener attempts to discriminate between two nonnative speech

segments, the possibilities are:

1. Two-category assimilation (TC) in which the nonnative segments are assimilated intodifferent native phonological categories, and discrimination is predicted to be

excellent;

2. Category-Goodness Difference (CG) in which both nonnative segments areassimilated to the same native phonological category, but they differ in that one

segment is a good exemplar of that native category while the other is deviant, and

discrimination should be moderate to very good depending on how big the difference

of category-goodness is;

3. Single-Category Assimilation (SC) in which both nonnative segments are assimilatedto the same native phonological category but are equally discrepant from the native

ideal, and discrimination should be poor;

4. Uncategorised versus Categorised (UC) in which one nonnative segment isassimilated to a native phonological category, whilst the other falls within the

phonetic space but not into any native phonological category, and discrimination

should be very good.

For a full description of possible perceptual assimilations see Best (1993; 1995).

PAM predicts that listeners will discriminate nonnative phones in reference to the

phonological categories of their native language. PAM was not originally designed to

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predict L2 learning. However, the original PAM framework has been extended to account

for L2 perceptual learning.

3.3 PAM-L2

PAM-L2 (Best & Tyler, in press) attempts to predict how extended L2 experience will

change a phonological system that has developed based on native language input. PAM-

L2 predicts that L2 learners will learn to perceive L2 segments with varying degrees of

success. When L2 learners encounter L2 minimal contrasts, they may:

1) Only perceive one of the two L2 phonological categories as equivalent (perceptually

assimilated) to an L1 phonological category. The learner would have little difficulty

discriminating minimal contrasts for these distinctions.

2) Perceive both L2 phonological categories as equivalent to the same L1 phonological

category, but one is perceived as being more deviant than the other. The deviant phone

would initially be learned as a new L2 phonetic variant of the L1 phonological category.

With experience, the learner should develop a new phonological category for the deviant.

3) Perceive both L2 phonological categories as equivalent to the same L1 phonological

category, but as equally good or poor instances of that category. The learner will have

trouble discriminating these L2 phones, which would be assimilated both phonetically

and phonologically to the single L1 category. Minimally contrasting L2 words would be

perceived as homophones (identical pronunciation).

4) Perceive both L2 phones as speech segments, but not assimilate either of them to any

L1 phonological categories. The phones may be heard as speech segments; but not as

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clear examples of L1 categories. As a result, the learner may form one or two new L2

phonological categories.

The predictions put forth by PAM-L2 will be tested by the present research, applied to

fluent Greek-Australian English early sequential bilinguals. However, the early bilinguals

who will be tested in the present research had far less L1 exposure when they began

acquiring their L2, as compared to the adult L2 learners that PAM-L2 was designed for.

The results of the present research are expected to extend the principles of PAM-L2 and

of SLM to explain performance of fluent early bilinguals.

4. Bilingual speech perception and production research

The research proposed in this thesis aims to improve our understanding of the structure of

the bilingual phonological system(s) and their finer-grained phonetic details. Research

involving bilingual participants has yielded mixed results regarding the nature of their

phonological system(s).

It is difficult to characterise the findings in the bilingual literature because some authors

only describe differences at the phonetic level while others address differences at both the

phonetic and phonological levels. This distinction is not always made clear and can lead

to ambiguity and misinterpretation. Moreover, results within individual studies

sometimes present seemingly ambiguous data. For example, bilinguals may appear to

have merged categories in one experiment, but may appear to maintain separate

categories in the following experiment. Part of this ambiguity can be attributed to the

complicated nature of research involving bilinguals. For these reasons, it is necessary to

interpret the results of bilingual studies with caution.

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Voice onset time (VOT) has long been established as a useful measure for characterising

cross-language differences in the production of voicing distinctions (vibrating vocal folds

= voiced; spread vocal folds = voiceless) between stop consonants which involve

complete closure of the articulators at some position in the vocal tract, temporarily

stopping the airflow (Lisker & Abramson, 1964). VOT is defined as the timing between

the release of the closure and the onset of vibration of the vocal folds (Lisker &

Abramson, 1964). It distinguishes voiced and/or prevoiced from voiceless stops within

most languages (e.g. /b/ vs. /p/), and provides a common basis for describing certain

cross-language differences in the acoustic-phonetic realisation of voicing contrasts. VOT

is especially interesting in cases where the bilinguals two languages make phonological

distinctions at different phonetic points along the VOT continuum, as in Greek versus

English.

If bilinguals produce values intermediate to those of monolingual speakers of the two

languages, this is taken as evidence of merged L1-L2phonetic categories that are used by

both languages. For example, Spanish-American English bilinguals produced /p, t, k/

with significantly longer VOT values in English words than in Spanish words, however,

their English word VOT values were significantly shorter than those of American English

(AmE) monolinguals (Flege & Eefting, 1987b). Note that Spanish /p, t, k/ are

implemented with short lag unaspirated VOT in utterance-initial position, while English

/p, t, k/ have long lag aspirated VOTs. In a separate task, the Spanish bilinguals category

boundaries of /da/-/ta/ were at significantly shorter values than those of AmE

monolinguals, consistent with the VOT differences between the languages (Flege &

Eefting, 1987b).

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Failure to identify a language-specific phonological contrast that exists in one language

but not the other is interpreted as evidence of a mergedphonologicalcategory. Numerous

studies involving Spanish-Catalan bilinguals in Barcelona have demonstrated that

Spanish-dominant early sequential bilinguals who have learned Catalan assimilate the

Catalan-specific /e/ and // vowels to the Spanish /e/ phonological category (Pallier,

Bosch & Sebastian-Galls, 1997; Sebastian-Galls & Soto-Faraco, 1999; Sebastian-

Galls, Echeverria & Bosch, 2005). In a repetition priming task, Spanish-dominant

bilinguals responded faster for pairs of words that only differed in a Catalan-specific

contrast, which indicated that they thought they had encountered the word for a second

time because they failed to discriminate the Catalan contrast, having treated the two

words as homophones (Pallier, Colome & Sebastian-Galls, 2001). Catalan-dominant

bilinguals did not respond faster for these minimal pairs, meaning that they discriminated

the two words because they had separate phonological categories of Catalan /e/ and //

(Pallier, Colome & Sebastian-Galls, 2001). It appears that the L1 shapes the perceptual

system at early stages of development in a way that determines the perception of

nonnative phonemic contrasts, even if there is early and prolonged exposure to the L2.

These findings provide strong evidence that early sequential bilinguals have an integrated

phonological system containing phonetic and phonological categories used by both of

their languages, and may be dominated by the L1.

In spite of evidence that bilinguals have a phonological system with merged categories

(Flege & Eefting, 1987b; Pallier, Colome & Sebastian-Galls, 2001), there is other

evidence suggesting that bilinguals maintain separate categories for their two languages.

Performance that is equal to that of monolinguals of either language is interpreted as

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evidence of separate L1 and L2 phonetic and phonological categories. For example,

AmE-Frenchbilinguals were almost indistinguishable from English monolinguals in their

discrimination of /d/-/t/ and /i/-// continua, the location of category boundary for /d/-/t/,

and the slope and fit of /i/-// regression lines (Mack, 1989). Note that French /d/ is

produced with voicing lead, /t/ is short lag unaspirated, and // does not exist in French. In

addition, the two groups were similar in their productions with respect to VOT, vowel

duration, and almost all spectral features associated with vowels (Mack, 1989). Note that

/i/ is one of the longest vowels in English, but one of the shortest in French. These

findings suggested that AmE-French bilinguals maintained a monolingual-like AmE

perceptual system not affected by their L2, French.

Thus, studies are inconclusive with regard to the phonological systems of bilinguals. On

the one hand, some evidence exists that suggests that bilinguals possess one phonological

system containing merged phonetic and phonological categories from both languages

(Flege & Eefting, 1987b; Pallier, Colome and Sebastian-Galls, 2001). However, it has

been suggested that bilinguals may keep their L1 and L2 categories separate (Mack,

1989). As a consequence, this issue remains unresolved and warrants further scientific

investigation.

Nevertheless, it is possible to draw some general conclusions from the existing literature.

There is strong evidence that bilinguals are uniquely configured as a result of their

language experience. In direct realist terms, language experience should result in a

perceptual attunement so that bilinguals are able to pick up contextual information from

the environment which affords them selective use of their two languages. If this is

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correct, then a shift in linguistic context should cause a corresponding shift in the

phonetic and phonological information that a bilingual uses in speech perception and

production.

4.1 The bilingual as a constantly changing perceiver-producer

Compatible with that notion, change in language use and language setting results in

changes of a bilingual's production of both L1 and L2 stop consonants (Sancier &

Fowler, 1997). A Brazilian Portuguese-AmE late bilingual participant traveled between

the United States and Brazil several times over the course of a year. Brazilian Portuguese

voiceless stops are short lag unaspirated, whereas in AmE, they tend to be long lag

aspirated. During her 4.5 and 4-month stays in the United States, the participant mainly

spoke AmE, and immediately upon her return to Brazil, native Brazilian Portuguese

listeners rated her Portuguese voiceless stops as significantly more explosive or

American-sounding than recordings before her trip to the United States. Acoustic

measurements confirmed that the speakers voiceless stop VOT values in hernative

language, Portuguese, had increased toward the longer values of English after her stay in

the United States (Sancier & Fowler, 1997). After a 2.5 month stay in Brazil, during

which she mainly spoke Portuguese, the participant returned to the United Sates.

Acoustic measures indicated that the speakers /p/ and /t/ in both languages had shifted

just as much, this time toward the shorter Portuguese VOT values (Sancier & Fowler,

1997). The speaker had experienced gestural drift in both of her languages towards the

VOTs of the language environment. These findings strongly suggest that a bilingual

possesses an interdependent L1/L2 phonological system containing L1/L2 categories that

are merged or at least linked. Given that productions in both languages were affected

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when only one language was used for a period of a few months, the L1 and L2

phonological systems cannot possibly be independent, at least not in production. In

addition, learning appears to be an ongoing process that may result in temporary and

context-dependentchanges in speech production well into adulthood. In this sense, the

bilingual speaker is in a constant state of change.

4.2 Manipulating the linguistic context in bilingual research

Linguistic context may provide a potentially important account for some of the

ambiguous findings in research involving bilinguals (Flege & Eefting, 1987b; Pallier,

Colome, & Sebastian-Galls, 2001; Mack, 1989). Researchers should heed language

mode at all times, as it may influence the results of a bilingual study, and if a researcher

does not wish to make such a manipulation, then it must be controlled for (Grosjean,

1998). Theories of speech perception (PAM; PAM-L2) and production (SLM) have not

considered the role that linguistic context can play in the performance of bilingual

participants. Similarly, researchers studying bilingual populations have usually ignored

language mode in their methodological designs. Some of the most influential speech

perception studies involving bilinguals have been those from researchers at the

Universitat de Barcelona. In almost a decade of research on Spanish-Catalan bilinguals,

no study has manipulated the language of presentation. Remarkably, in the studies

conducted by the Barcelona group, the language used by the experimenter has not been

reported at all (Pallier, Bosch, & Sebastian-Galls, 1997; Sebastian-Galls & Soto-

Faraco, 1999; Pallier, Colome, & Sebastian-Galls, 2001; Sebastian-Galls, Echeverria,

& Bosch, 2005). This suggests that the researchers have not considered the role played by

the linguistic setting in which research takes place. This lack of interest is puzzling when

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one considers that the majority of the few studies that have manipulated the language of

presentation have yielded significant results.

One reason why linguistic context has been overlooked by researchers may be because

the initial two studies which attempted to put bilinguals in a monolingual mode yielded

results that suggested that the language of presentation did not exert a significant

influence on bilinguals perception. The first study to manipulate the language of

presentation examined the perception and production of stop consonants in bilingual

Canadian French-Canadian English speakers (Caramazza, Yeni-Komshian, Zurif, &

Carbone, 1973). The researchers tested the bilingual group using an English experimenter

in an English university and a French experimenter in a French high school. All stimuli,

materials and instructions were in the language of the experimenter. The bilinguals

produced French VOTs almost identical to French monolinguals. When producing

English words, the bilinguals VOTs shifted, but did not completely match the English

monolinguals. These results indicate that the two languages are not separate but inter-

dependent in bilinguals, and provide some (albeit limited) evidence that language mode

can influence bilingualproduction. However, the bilingualsperception scores were in

between the two groups of monolinguals. It seemed that bilinguals were able to adapt

their production mechanisms, but not their perceptual mechanisms, to the second

language. In perception, the stimulus, rather than the language mode, seemed to

determine the type of analysis to be performed (Caramazza et al., 1973).

Language of presentation was manipulated in a similar fashion in a VOT study of the

perception and production of Spanish-English bilinguals (Williams, 1977). The

productions made by bilinguals in both languages were similar to the results obtained

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from monolingual speakers of each language. However, in perception, the bilinguals

divided a synthetic VOT continuum into voiced and voiceless domains at a compromise

point in between the Spanish or English monolingual groups. Language of presentation

did not appear to influence the bilinguals perception.

However, upon closer inspection, a number of methodological issues can be identified

that question the validity of Williams data. The bilingual group contained some

participants who were English-dominant and others who were Spanish-dominant.

Language dominance may exert a stronger effect than language of presentation (Hazan &

Boulakia, 1993), and therefore, may have confounded any potential linguistic context

effect. Furthermore, the manipulation of language of presentation employed by Williams

(like Caramazza et al., 1973) was not sufficient to keep the bilingual listeners in a

monolingual mode. Providing instructions in one language will only determine what the

base language will be but will not deactivate the other language and keep participants in a

monolingual mode (Grosjean, 1998). Some of the stimuli would have been heard several

minutes after the language-specific instructions had been given, thereby reducing the

effectiveness of the language of presentation. Consequently, the bilinguals produced

intermediate results between those of the two monolingual groups in both language

presentation conditions. Had these researchers used natural tokens and provided constant

language-specific reminders (such as filler words or carrier phrases), the manipulation

might have been effective.

The most carefully designed manipulation of language of presentation in speech

production was conducted by Magloire and Green (1999) who examined the effect of

speaking rate on VOT of Spanish and English voiced and voiceless bilabial stops.

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Initially, bilingual participants were tested in an English presentation condition they

were contacted, instructed, and spoken to only in English. The experimenter made no

mention of their bilingual status during the testing procedure. During the debriefing, the

experimenter pointed out that an item on the questionnaire indicated that the participant

spoke Spanish, and then asked the participant to participate in a future Spanish study.

Participants were kept naive of the fact that the two experiments were part of the same

study. Spanish-English bilinguals produced VOT values in each language that were

nearly identical to their monolingual counterparts, even when their articulation was

stressed under very fast and slow speaking rates (Magloire & Green, 1999).

The first perceptual study which firmly established its participants in a monolingual

language mode was conducted by Elman, Diehl and Buchwald (1977). Naturally

produced stimuli were preceded by a carrier phrase in each language (Spanish and

English). In addition, same-language filler words were placed between test items. The

five test syllables had VOT values of -69, +15, +19, +26, and +66 milliseconds. In a pilot

study, both English monolinguals and Spanish monolinguals identified the - 69 stimulus

as /b/ and the +66 stimulus as /p/. The three intermediate stimuli were ambiguous in the

sense that English monolinguals heard them as /b/, whereas Spanish monolinguals heard

them as /p/. Bilinguals perceived the ambiguous stimuli as English, or as Spanish,

depending on the language of presentation (Elman, Diehl, & Buchwald, 1977). The

natural stimuli, the carrier sentence and the filler words provided constant language-

specific information which activated one language much more than the other and kept the

bilinguals at the monolingual end of the continuum (Grosjean, 2001). Bilinguals

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processed the stimuli in a more monolingual-like fashion, both in Spanish and English,

and this resulted in a language-specific boundary shift.

Of all the studies that have manipulated the language of presentation, only one was

designed with the sole purpose of examining the effect of the language of presentation on

bilingual perception and production (Flege & Eefting, 1987a). Dutch-English bilinguals

were compared to British English native speakers in their identification of a /d/-/t/

continuum. Note that Dutch /t/ is short lag unaspirated and /d/ is prevoiced. The Dutch-

English bilinguals had begun learning English at the age of 12. Instead of carrier phrases,

language-specific questions were inserted between blocks of trials which participants

were required to answer. This required that participants concentrate during the task.

Surprisingly, recorded instructions were used and the experimenter minimised his contact

with participants. The reason for this was to reduce the possibility of psychosocial and

sociolinguistic effects (Flege & Eefting, 1987a). This reasoning is somewhat

contradictory, as any effect of language mode must surely involve some interaction with

human speakers. Despite the facts that participants were made aware of the researchers'

interest in their bilingualism, and the minimal experimenter interaction, Dutch-English

bilinguals' category boundaries occurred at longer values in the English presentation than

in the Dutch (Flege & Eefting, 1987a). This finding directly contradicts those of previous

language of presentation studies that used synthetic stimuli yet failed to find perceptual

effects of language mode (Caramazza et al., 1973; Williams, 1977). This may have been

because the procedures used in this study were more effective (e.g. questions between

trial blocks), and the synthetic stimuli were more natural-sounding (Flege & Eefting,

1987a). The cross-language difference in VOT seen in speech production was larger than

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the perceptual category boundary shift between /d/-/t/. Despite their ability to shift VOT

in Dutch and English, Dutch-English bilinguals produced English /t/ with shorter VOTs

(60ms) than native speakers of English (90ms). Interestingly, Dutch-English bilinguals

with the best English accents produced Dutch /t/ with shorter VOTs than bilinguals with

stronger nonnative accents. It appeared that learning English had influenced their

productions of stops in their native language.

Given the findings of Elman et al. (1977) and Flege & Eefting (1987a), it appeared that a

shift in bilinguals perception could occur if language of presentation was adequately

manipulated. French-British English bilinguals were tested in their production and

identification of edited natural /bn/-/pn/ tokens (Hazan & Boulakia, 1993). Separate test

sessions were conducted in French and English: all conversations, instructions and

questionnaires were only in one language. Each stimulus was preceded by the word

repeat (English) or rptez (French). A clear effect of language of presentation was

found in production English-dominant bilinguals produced VOT values similar to

monolinguals in the respective language modes. French-dominant bilinguals produced

monolingual-like VOTs in French words, but only intermediate VOT values in English

words. However, these were significantly different from their French productions. In

addition, small but significant perceptual shifts in phoneme boundaries were found for

bilinguals in identification. Stronger bilinguals rated as having native-like accents

showed greater evidence of boundary shifts in perception. These results indicate that

bilingual production and perception can vary depending on language mode.

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If language mode can shift perception of L1 and L2 segments, then it follows that it

should also influence the perception of nonnative contrasts. The perceptual abilities of

Caribbean Spanish-English bilinguals were investigated in discrimination and

identification tasks using bilabial stop voicing contrasts from Xhosa (Calderon & Best,

1996). Bilinguals were divided into Spanish or English language presentation groups,

meaning that all contact and instructions were given in only one of the bilinguals

languages throughout the course of the study. The Spanish presentation condition, but not

the English condition had a negative effect on performance with the Xhosa prevoiced

implosive //- prenasalised plosive /m

b/ contrast. Note that neither of these consonants

occur in Spanish or English. The VOT values of Xhosa // and /mb/ (-60ms and -109ms,

respectively) are located towards the prevoiced Spanish /b/ (-130ms). The VOT range of

Spanish /b/ may have impeded the bilinguals ability to discriminate this Xhosa

distinction. Bilinguals in the English presentation condition discriminated the Xhosa //-

/mb/ contrast because the prenasalised consonant /

mb/ can be heard in English as an m+b

cluster, which differs phonologically from b, the English consonant to which the

implosive // was assimilated. The language of presentation put bilinguals into Spanish or

English monolingual mode, which affected the way that their phonological system

constrained their perception of the nonnative //-/mb/ contrast. These findings provide

strong evidence indicating that bilinguals are sensitive to linguistic context, even when

perceiving unfamiliar nonnative contrasts.

While no study that has manipulated the language of presentation has involved Greek-

Australian English bilinguals, Greek-Australian English bilinguals have been compared

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to Australian English (AusE) monolinguals in their production of bilabial stops and

perception of nonnative Thai bilabial stop voicing contrasts (Beach, Burnham &

Kitamura, 2001). Because the Greek-AusE bilinguals produced stops in both languages,

this study is useful for hypothesising how Greek-Australian English bilinguals will

perform in our proposed research. Greek-AusE bilinguals and AusE monolinguals

produced almost identical VOTs for AusE [ph], 76ms and 75ms respectively. Greek-

AusE bilinguals produced shorter VOT values for the unaspirated voiceless Greek /p/

(38ms) than their production of the long lag aspirated AusE [ph] (76ms). AusE [b] was

more prevoiced by the Greek-AusE bilinguals (-56ms) compared to the AusE

monolinguals (-13ms). The Greek bilinguals produced Greek [b] (-102ms) with more

voicing lead than their production of AusE [b] (-56ms). This suggested that Greek-AusE

bilinguals had separate phonetic categories for Greek [b] and AusE [b]. In a second

production task, participants imitated a native Thai speakers productions of Thai bilabial

stops. Greek-AusE bilinguals produced VOTs that were more extreme (more negative for

voiced, more positive for voiceless) than the Thai models and the AusE monolinguals.

In an AX discrimination task, participants were presented three nonnative Thai contrasts:

/ba/-/pha/, /pa/-/p

ha/, and /ba/-/pa/. The VOT values of the Thai stops are /ba/ (-103ms),

/pa/ (7.8ms), and /pha/ (71.9ms). Greek-Australian bilinguals were more successful at

discriminating the Thai /ba/-/pa/ contrast than AusE monolinguals. Interestingly, a link

was found between production and perception: Greek-AusE bilinguals who exaggerated

their productions of Greek versus English VOT discriminated Thai /ba/-/pa/ like Thai

native speakers (Beach, Burnham and Kitamura, 2001). However, the researchers did not

manipulate the language of presentation, language dominance differed within the

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bilingual group, two of the participants were simultaneous bilinguals, and no Greek

monolingual data were collected. There was a high degree of individual variation in the

Greek-AusE bilinguals productions which may have been reduced if the bilinguals had

the same language dominance, and had acquired their languages in the same order and at

similar ages. The present research will address all of these shortcomings.

In all, the evidence presented here indicates that the effect of language mode on both

perception and production warrants further investigation and theoretical explanation. As

has been argued, no author has presented a theoretical account of how and why language

mode effects occur in bilingual speech production and perception. Providing such an

explanation is a central goal of the present proposal.

5. The proposed research

The proposed study will systematically examine the effects of language of presentation

on early bilingual perception and production of stop voicing contrasts at the phonetic

level of gradient physical details. With the exception of Flege and Eefting (1987a), past

studies that have manipulated the language of presentation have had other primary aims

(Caramazza et al. 1973; Williams, 1977; Elman, Diehl & Buchwald, 1977; Hazan &

Boulakia, 1993; Calderon & Best, 1996; Magloire & Green, 1999), and have included a

language of presentation manipulation as a secondary goal. Note also that the Dutch-

English bilinguals in the Flege and Eefting (1987a) study had acquired their L2 late, at

the age of 12. Our research will focus on the production and perception of stop

consonants by Greek-AusE bilinguals who have acquired their L2 English much earlier,

by 4-5 years of age. Recall that Beach, Burnham and Kitamura (2001) tested Greek-AusE

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bilinguals. In the present research, the performance of the English (L2) dominant, Greek-

AusE early sequential bilinguals will be compared to that of groups of AusE and Greek

monolinguals.

5.1 Target languages

The proposed study will involve acoustic analyses of Greek and AusE stop consonant

productions, as well as the identification and discrimination of AusE, Greek, and Xhosa

stop consonants in a variety of contexts. Most bilingual research has examined Spanish-

Catalan, French-English, or Spanish-English language pairs. Greek and English are more

distant languages with less historical contact and fewer structural similarities than these

other language pairs (Algeo & Pyles, 1993). While English contains Greek borrowings,

they are largely restricted to scientific terms, and are typically pronounced according to

English phonology and phonetics, not Greek. For these reasons, Greek and English are

useful languages for testing the predictions of SLM, PAM and PAM-L2 extended to

bilinguals. We have decided to investigate stop consonants that differ in voicing because,

as with past research conducted on Spanish-English and French-English, Greek and

English differ in the phonetic settings of VOT used for stop voicing distinctions.

However, importantly, Greek and English also differ in the phonological status of voiced

versus voiceless stop consonants in ways that are not evident in the other languages that

have been compared in bilinguals, as will now be explained.

5.1.1 Australian English phonology

Australian English (AusE) is a non-rhotic dialect of English, spoken by most (but not all)

native-born Australians. It differs from other varieties of English primarily by its vowel

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phonology. AusE contains 12 monophthongal vowels 6 short vowels /, e, , , , /

and 6 long vowels /i, e, , o, , / and 6 diphthongs /, e, , , , / (Cox,

2006). AusE contains 24 consonant phonemes. The consonant system of AusE does not

differ greatly from most other dialects of English. The proposed research is concerned

with stop consonants, so I will only describe the AusE stop consonants.

AusE contains three voiceless (plosive) stops: the bilabial /p/, the alveolar /t/, and the

velar /k/. Voiceless stops may be long lag aspirated VOT (where there is a delay between

the release of the consonantal constriction and the beginning of voicing) or short lag

unaspirated VOT (where voicing begins at the time of the release or shortly afterwards)

depending on the context in which they occur. Voiceless stops are aspirated in word-

initial position and in stressed syllable-initial position (e.g. push [ph], support

[sphot], tin [thn], factorial [fkthor], cow [kh], and accord [khod]:

Cox & Palethorpe, in press). At the beginning of an unstressed syllable, voiceless stops

are usually shorter-VOT and weakly aspirated (e.g. beeper [bip], looking [lk]).

Voiceless stops are always unaspirated when preceded by [s] within the same syllable

(e.g. spin [spn], stop [stp], and skin [skn]; Cox & Palethorpe, in press).

AusE contains three voiced (plosive) stops: the bilabial /b/, the alveolar /d/, and the velar

/g/. Voiced stops have short lag unaspirated VOT in word -initial position, where /b/, /d/,

and /g/ are realised as [p], [t] and [k], e.g. back [pk], dig [tg]), go [k]. But in

intervocalic (between-vowel) stress-initial position they are realized as fully voiced (e.g.

abort [bot], adore [do], again [gen]; Cox & Palethorpe, in press).

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Note that the alveolar stops /t/ and /d/ may, in some contexts, be realised as taps

(Tollfree, 2001; Cox & Palethorpe, in press). Alveolar stops may be realised as an

alveolar tap [] at the beginning of an unstressed syllable that is not at the beginning of a

word (e.g. lighter [le], and ladder [l]).

Thus, in general, AusE VOT values become more extreme (voiced negative, voiceless

positive) in stress-initial position.

5.1.2 Greek phonology

Greek is an independent branch of the Indo-European language family. Over its 3,300

year written history, the Greek language has undergone a number of changes, however,

its dialects have never developed into mutually incomprehensible languages. Standard

Modern Greek, the official language of the Hellenic Republic of Greece, is spoken by

approximately 15 million people in Greece, Cyprus, Albania, Bulgaria, the Former

Yugoslav Republic of Macedonia, Italy and Turkey. There are also many Greek emigrant

communities around the world including the United States, Canada, Germany, and

Australia.

Standard Modern Greek (henceforth MG) contains the same 24 letters in its writing

system as Classical (Ancient) Greek. However, there is no universally accepted list of

MG phonemes in spoken Greek. Generally speaking, MG is said to contain between 15 to

26 phonemes, with most accounts ranging from 20 (Newton, 1961; Warburton, 1970;

Holton, Mackridge, and Philippaki-Warburton, 1997) to 23 (Koutsoudas & Koutsoudas,

1962; Householder, Kazazis, and Koutsoudas, 1964; Setatos, 1974; Mackridge, 1985). It

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is uncontested that there are only five vowels in MG: /a, e, i, o, u/. Vowel length is not a

distinctive feature, although vowels are slightly longer when stressed. Where there is

disagreement is about the number of consonants. MG contains 26 consonant phones,

however, the phonological status of a number of these phones is the subject of

longstanding academic debate.

The present proposal will investigate the production and perception of Greek stop

consonants, so I will therefore limit my discussion here to MG stop consonants. MG

contains the voiceless stops bilabial /p/, dental /t/, and dorso-velar /k/. The VOTs of

voiceless stops are always short-lag unaspirated in MG, regardless of stress or syllable

position. The phonological status of each of the voiceless stops is widely accepted by

Greek linguists.

Over the past fifty years, however, one of the most passionately debated aspects of Greek

phonology has been the status ofvoicedstops in MG. There is no denying that the voiced

stops [b, d, g] occurphonetically in MG. However, the phonological status of these

segments remains unclear.

There are two sources of voiced stops in MG. Historically, most voiced stops came from

Classical Greek sequences of nasal + voiceless stop. This provides an intuitive and

uncomplicated method of predicting the occurrence of voiced stops by rule. This rule is

doubly tempting when one examines Greek orthography, where voiced stops are

represented by a digraph consisting of a nasal and a stop. For example, b = (/m/+/p/),

d = (/n/+/t/), and g = . In the Athenian dialect of MG, word-initial position voiced

stops are pronounced as [b, d, g]. In word-medial position, they are prenasalised [mb,

nd,

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ng], except when following a liquid (i.e., /r/ or /l/). Note also that prenasalised voiceless

stops [mp,

nt,

nk] do not occur in MG.

However, voiced stops also entered the MG language through foreign loan words,

particularly during the period of Turkish occupation (1453-1829) and also from the

Venetian dialect of Italian. Both of these languages contain voiceless and voiced stops as

contrastive segments. This is where the tension arises, between elegant simplicity and

empirical completeness (Viechnicki, 1995). The reality is that loan words have been

accepted into the Greek language and must be accounted for. Loan words exist in

everyday MG that do not follow the Greek phonotactic (phoneme-sequencing) rules

outlined above. For example, words such as [sampanja] (champagne) or

[kompjuter] (computer) are pronounced as nasals + voiceless stops.

To further complicate matters, when variations in dialect, idiolect, rate of speech, and

social register are taken into account, the variation in pronunciation is tremendous. For

example, the word ('man') would be pronounced [andras] in the Peloponnese,

[adras] in Crete, and [andras] in Athens with [d] slightly prenasalised (Viechnicki, 1995).

There have been reports that more prenasalisation occurs in slow speech, and also that it

varies according to context, possibly with an emphatic function. Variation also exists

with some words, in some dialects, that permit the use of prenasalisation of a voiced stop

in word-initial position.

So far, I have only discussed individual words. Nasals and voiceless stops may also

combine across word boundaries, resulting in prenasalised voiced stops. For example, if

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the accusative article [ton] is followed by the name [Petro], this may be

pronounced [tombetro].

A number of proposals have attempted to account for voiced stops in MG, however, none

can address all these factors. A common argument for the recognition of [b, d, g] as

separate phonemes is the existence of minimal pairs such as [beto] - [peto],

[kapos] [kampos], and [tinos] - [dinos]. To complicate

things even more, the notion of prenasalisation in MG is controversial in itself. Some

linguists do not use the term at all, and those who do use it describe different things.

When it comes to the phonological status of MG voiced stops there is anything but

consensus.

Regardless of the phonemic status of the MG sounds [p, t, k] and [b, d, g], they

incontestably exist as phonetic categories in Greek. Given that these are phonemes in

AusE, but that they are produced with different VOTs than those of MG, questions

regarding the production and perception of voiced and voiceless stops of both languages

by Greek-AusE bilinguals must be addressed.

5.1.3 Xhosa Phonology

Xhosa sounds have been chosen for perceptual tests of nonnative stop voicing contrasts

in Experiment 3 because they are expected to be perceptually assimilated differently by

our different groups of listeners. Also, participants are unlikely to have had previous

experience with this language.

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Xhosa is a South African language spoken by people of Bantu origin. The three bilabial

Xhosa sounds relevant to this research will now be described. The implosive // is

produced with voicing lead (-60ms), which is presumably similar to the Greek /b/.

Voiced implosives require the larynx to be lowered during the oral closure, while the

vocal folds are vibrating. The voiced plosive /b/ is produced with short lag VOT (+9ms),

which is similar to English /b/, and presumably Greek /p/. The prenasalised /mb/ (-109ms)

contains a full murmured pre-voicing period, thus similar to initial voiced /b/ or medial

prenasalised /mb/ in Greek. The nasalisation of /

mb/ is a result of the velum being lowered

during the articulation of the plosive segment.

5.2 Rationale

One central goal of the proposed research is to combine principles of SLM, PAM, and

PAM-L2 with language mode and inhibitory control, to account for how linguistic

context affects a bilinguals performance in perception and production tasks. Existing

models of bilingualism have demonstrated the importance of linguistic context in

bilingual language use. Bilinguals may effortlessly move along a monolingual-bilingual

continuum and/or change their base language (Grosjean, 1989, 1998, 2001). The

language-specific input (heard or read words) of the linguistic context will inhibit words

that have different language tags, enabling bilingual word selection (Green, 1998). Given

that cross-linguistic research has demonstrated that bilinguals are sensitive to the

linguistic context when producing speech (Flege & Eefting, 1987a; Hazan & Boulakia

1993; Magloire & Green, 1999), perceiving native phones (Elman, Diehl, & Buchwald,

1977; Flege & Eefting, 1987a; Hazan & Boulakia, 1993), and perceiving nonnative

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phones (Calderon & Best, 1996), any theory attempting to account for bilingual speech

perception and production must address the effect of linguistic context.

Existing cross-linguistic models have attempted to predict how naive listeners will

perceive nonnative contrasts (PAM), how people who are acquiring an L2 will

discriminate L2 contrasts (PAM-L2), and produce L1 and L2 phones (SLM). L2

experience changes a persons phonological system, and some L2 contrasts will be

perceived correctly, while others will not (Best & Tyler, in press). If L2 phones are

perceived inaccurately speech may be accented, particularly by late L2 learners (Flege,

1995). However, fluent bilinguals are not actively acquiringeither of their languages.

They have reached a level of language stability and are comfortable using both of their

languages every day, often interchangeably. This, of course, does not imply that they do

not have a dominant language. It is argued that bilinguals always have a dominant

language (be it the L1 or the L2). Nor does it imply that bilinguals ever stop learning. On

the contrary, any effect of linguistic context is evidence that bilinguals are able to learn

and adapt. However, this learning differs from L2 acquisition, and for this reason fluent

bilinguals are not L2 learners. In order to predict the performance of fluent early

bilinguals in perceptual and production tasks, a new framework is required one which

combines the principles of the existing theories outlined above.

5.3 The Perceptual Assimilation Model of Early Bilinguals (PAM-EB)

The aim of the proposed PAM-EB framework is to explain and predict early bilinguals

performance in perception and production relative to monolinguals of each language.

Consistent with the assumptions of PAM (Best, 1995) and PAM-L2 (Best & Tyler, in

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press), PAM-EB assumes that bilinguals possess an integrated phonological system. This

integrated system will contain L1, L2, and merged phonetic and phonological categories,

which have been formed as a direct result of the bilinguals linguistic experience.

The core tenet of PAM-EB is that fluent bilinguals are sensitive to the linguistic context,

and are able to shift their perception and production when in different language modes.

These shifts are reliable, and directly depend upon the linguistic context. These shifts are

possible because phonetic categories are tagged with a language label. It is hypothesised

that speech will be assimilated to categories with the same language tag as the language

of presentation (or context). From a direct realist perspective, the systematic

manipulation of language of presentation can bring about short term perceptual

reattunement. This can be thought of as analogous to selective attention in the

mainstream cognitive sciences. The effects of this reattunement are that bilinguals will be

sensitive to language-specific gestural information in the speech stream. Based on shifts

in performance in these different language modes, it is possible to draw inferences

concerning the phonological systems of bilinguals.

It is hypothesised that fluent bilinguals are able to produce L2 phones approaching the

productions of monolingual speakers if the L1 and L2 phones are perceived as dissimilar.

When a phonological category is produced with a different place of articulation in the L1

and L2 (e.g. AusE /t/ alveolar vs. Greek /t/ dental), fluent bilinguals will shift the place of

articulation when producing phones in the different languages.

When bilinguals fail to identify differences in the gestural constellations of L1-L2 phones

(e.g. AusE /b/ vs. Greek /b/ which differ in their phasing of laryngeal gesture to bilabial

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release gesture), the production of L2 phones will be unlike that of monolinguals.

Language specific contrasts (L1-L1 or L2-L2) will be best discriminated in that language

mode (monolingual L1 or L2 mode), however, discrimination will be impeded in the

wrong language mode (e.g. [b] vs. [p] will be discriminated in Greek mode, but not in

English mode). Nonnative contrasts predicted to be successfully discriminated by

speakers of one of the bilinguals languages (according to PAM) will be discriminated in

the appropriate language mode. However, discrimination of nonnative contrasts will be

impeded if the bilingual is in a language mode in which the nonnative phones do not

contrast.

6. Experiments: Investigating the effects of language of presentation on bilingual

speech production and perception

6.1 Ethics approval

In accordance with the National Statement on Ethical Conduct in Research Involving

Humans of June 1999, UWS requires that all PhD students obtain their own ethics

approval from the University of Western Sydneys Human Research Ethics Committee.

This application, including the necessary attachments (participant information statement,

consent form etc.) is in preparation. No research will commence until the Ethics

Application has been approved. Separate ethics applications will be prepared for testing

that will occur in Greece and in Australia. This is indicated in the research timeline.

Submission of the Ethics Application for the research in Australia is expected to happen

in time for the next HREC application deadline of 2nd February 2007.

6.2 Experiment 1: Production of Greek and AusE stop voicing: /p, t, k/ vs. /b, d, g/

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6.2.1 Aim

The aim of Experiment 1 is to acoustically measure the productions of stop consonants in

initial and medial (stressed and unstressed) contexts. No comprehensive investigation of

stop consonant production has ever been conducted on Greek speakers. It is required to

measure Greek monolinguals productions of stops as these measures will provide

invaluable information for deriving hypotheses in subsequent perceptual experiments.

The productions of AusE monolinguals will also be acoustically analysed. Experiment 1

will also examine the effects of language of presentation on Greek-Australian bilinguals

stop consonant production.

6.2.2 Study design

Participants will be required to produce stop consonants in three contexts:

1. Word-initial CV /pa, ta, ba, da/

2. Word-medial VCV /apa,ata,aba,ada,with stress on the first syllable ampa, anta, amba, anda/

3. Word-medial VCV /apa,ata, aba,ada,with stress on the second syllable ampa, anta, amba, anda/

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The reason for using these three word contexts is that stress has been shown to result in

longer VOT values in English (Cooper, 1991). Note that in the word-medial contexts,

some stops are nasalised to test the effects of Greek phonotactic rules on Greek listeners

production and perception. In addition, the rationale for including stops from two places

of articulation is that VOT values increase as the place of closure moves further back into

the oral cavity, in English (Dorman & Raphael, 1980). We need to assess whether this

effect also occurs in Greek. Furthermore, Greek and AusE differ in the place of

articulation for /t/ and /d/ (AusE alveolar, Greek dental) and we plan to examine

whether this occurs systematically in the productions of our monolinguals and bilinguals.

The Greek and AusE monolinguals will be tested in their respective languages. Greek-

AusE bilinguals will be tested in the language of presentation (either Greek or AusE).

This means that all contact, instructions, stimuli, sheets, feedback and conversations will

only be in one language. For example, the carrier phrases for the respective languages

will be: say (word) again or >.

Participants will have time to familiarise themselves with the words on a sheet before

they are recorded. Participants will be instructed to produce the words at a normal

speaking rate, as though they are speaking to a friend.

Three productions of each stop consonant in each context will be recorded. This will

generate a total of 1920 utterances for acoustic analysis (3 productions x 20 word

contexts x 32 speakers). Target words will be excised from the recordings using PRAAT.

Acoustic measurements will be made for acoustic variables known to cue the voicing

distinction: target VOTs, F0 contour, F1 onset, and F1 cutback (Lisker, 1978).We will

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measure formant onset frequencies or other acoustic measures of place of articulation to

determine whether place of articulation differs between Greek and English /d/-/t/ but not

/b/-/p/. We will also attempt to measure nasalisation in voiced stops in all positions.

6.2.3 Predictions

While the exact VOT values produced by Greek monolinguals are not yet known, it has

been claimed that Greeks produce voiced stops with voicing lead and voiceless stops with

short lag (Beach, Burnham, & Kitamura, 2001). Recall that AusE monolinguals produce

stress-initial voiced stops with short lag and voiceless stops with long lag. Based on these

cross-language differences, it is possible to put forth the following predictions from PAM

for monolinguals:

1. AusE monolinguals will produce longer word-initial VOTs than Greekmonolinguals for both voiced and voiceless stops;

2. AusE monolinguals will produce more extreme VOTs (more positive voiceless,more negative voiced) in medial stops when the syllable beginning with the stop

is stressed than when it is unstressed.

3. Given that we do not yet know the effects that syllabic stress has on Greek VOT,we cannot make a specific prediction regarding how stress will affect the Greek

monolinguals productions.

Consistent with the proposed PAM-EB framework, the language of presentation will

result in a shift in Greek-AusE bilinguals production of VOT:

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4. Greek-AusE bilinguals in the English language of presentation condition willproduce longer word-initial VOTs than Greek-AusE bilinguals in the Greek

presentation condition;

5. For the voiceless stops [ph] and [th], Greek-AusE bilinguals in the Englishpresentation will produce word-initial VOTs equal to those of AusE

monolinguals;

6. For prevoiced stops [b] and [d], Greek-AusE bilinguals in the Greek presentationwill produce word-initial VOTs equal to those of Greek monolinguals;

7. Greek-AusE bilinguals in the English presentation will produce more extremeintervocalic VOTs when the syllable containing the stop is stressed;

8. It is not yet known what effect syllabic stress has on Greek VOTs, but it can bepredicted that if there is a cross-linguistic difference, then bilinguals in the Greek

presentation will produce Greek-like VOTs for prevoiced stops.

9. The coronal stops /d/-/t/ will be morefronted(dental) in the Greek presentationand more backed(alveolar) in the AusE presentation. This will be indicated in the

formant onset frequency measures.

Note that SLM would predict that Greek-AusE bilinguals productions would not be

equal to that of Greek monolinguals (Greek predictions 5 and 7) due to their extended

experience with their L2 AusE. Moreover, SLM would predict that Greek-AusE

bilinguals productions of English long lag aspirated stops would be equal to AusE

monolinguals (AusE predictions 4 and 6) because long lap stops are very different from

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any L1 (Greek) phonetic category, i.e., new L2 categories should be formed in these

cases.

6.2.4 Participants and recruitment

The AusE monolingual group (n = 8) will be recruited from the student population at

UWS. They will be monolingual native speakers of AusE, between 20-40 years of age,

with no history of speech, language or hearing disorders.

The Greek monolingual group (n = 8) will be recruited from the student population at the

National and Kapodistrian University of Athens. They will be native speakers of Greek

with limited proficiency and exposure to English, aged between 20-40 years, with no

history of speech, language or hearing disorders. Ethics approval will be obtained before

recruitment and testing begin.

The Greek-AusE bilinguals (n = 16) will be recruited from within the UWS student

population, the Greek societies of other universities within Sydney, and the Greek

community of Sydney in general possibly through newspaper advertisements and

pamphlets/posters. To be eligible, they must have been exposed to, and acquired, Greek

since birth and have acquired English by the age of five. In addition, bilinguals must be

highly fluent in both languages and use both every day.

All participants will be asked to complete a language background information sheet.

Language background information sheets will be provided in the language of presentation

(see Appendix A and B).

6.3 Experiments 2A-2C Perception of Greek and AusE stop voicing distinctions

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6.3.1 Aims

Experiment 2 will test the discrimination predictions of PAM-EB (adapted from PAM-

L2) concerning perceptual shifts brought about by the language of presentation effects in

Greek-English bilinguals. Predictions made by PAM will be tested by the monolinguals

perception of nonnative phones (Greek monolinguals AusE stops, AusE monolinguals

Greek stops). New groups from the same participant populations described above will be

recruited and tested on an identification task with ratings (testing for assimilation to

native language phonemes or to language of presentation for bilinguals) and also an AXB

discrimination task, for all stimulus contrasts described below. Both tasks are necessary,

as the combined results will provide the information needed to determine how the sounds

were perceptually assimilated and discriminated. Experiment 2 will be divided into three

sub-experiments, based on positional context: word-initial, word-medial stressed, and

word-medial unstressed.

6.3.2 Study design

If the results of Experiment 1 show that Greek-AusE bilinguals (in the respective

language presentations) shift their VOTs towards those of monolinguals, the speech of

four Greek-AusE bilingual speakers will be recorded to be used as stimuli in Experiment

2. If the bilinguals fail to shift their VOTs, four Greek and four AusE monolingual

speakers will be recorded instead (this possibility has been anticipated in the timeline).

Three tokens will be recorded of each speaker producing each stop in each context. Note

that if the speech of monolingual speakers is recorded, tokens from different speakers

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will be used to make up the triads of tokens for the AXB discrimination task. This will

ensure that listeners will not be using speaker-specific cues to make their responses.

The target sounds /p/-/b/ and /t/-/d/ will be presented in both languages in three word

contexts. Testing will only involve within-language pairings. Note that while the short lag

unaspiratedphonetic entities are similar in AusE and Greek, thephonologicalcategories

of the respective monolingual groups will differ (e.g. [p] is an allophone of AusE word-

initial /b/ but of Greek /p/).

As in Experiment 1, Greek and AusE monolinguals will be tested in their respective

languages. Greek-AusE bilinguals will be tested in the language of presentation (either

Greek or AusE). For example, their answer sheet will indicate tick what you hear or

.

6.3.3 Experiment 2A Word-initial position CV

Predictions

Based on the phonological distinctions made in AusE and in Greek, it is predicted

from PAM that for monolinguals:

1. AusE monolinguals will discriminate word-initial long lag aspirated stops (e.g.[p

h]) from short lag unaspirated and voicing lead stops. AusE listeners will be

unable to distinguish the voicing lead stops from the short lag unaspirated stops

both are predicted to be assimilated to a single category, an AusE voiced stop

(e.g. [b] and [p] both = /b/ in AusE).

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2. Greek monolinguals will discriminate stops produced with voicing lead fromshort lag unaspirated and long lag aspirated. Greeks may distinguish short lag

unaspirated stops from long lag aspirated, as they should be perceptually

assimilated as good (short lag) versus poor (long lag) exemplars to the same

phonological category, a Greek voiceless stop.

Based on the hypotheses of PAM-EB, it is anticipated that bilinguals will shift their

perception and assimilate to Greek or English depending on the language of presentation:

3. Bilinguals in the English presentation will discriminate long lag aspirated stopsfrom short lag unaspirated, but will not distinguish the voicing lead stops from the

short lag unaspirated;

4. Bilinguals in the Greek presentation will discriminate voicing lead stops fromshort lag unaspirated. They will distinguish the short lag unaspirated stops from

long lag aspirated as a category-goodness assimilation.

6.3.4 Experiment 2B Word-medial position VCV

Note that Experiment 2B-2C predictions concerning Greek stops may change depending

on the results of Experiment 1.

Predictions

Based on the predictions of PAM for monolinguals:

1. AusE monolinguals will discriminate unstressed intervocalic long lag aspiratedstops (e.g. AusE [p

h]) from the short lag unaspirated (e.g. AusE [p]);

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2. AusE monolinguals will discriminate voiceless and voiced

mark antoniou coc final

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