A comparative acoustic study of hanoi vietnamese and general american english monophthongs m a thesis linguistics 60 22 15

Vietnam national university, Hanoi University of languages and international studies Faculty of Post graduate studiesDOÃN MINH MÃO A comparative acoustic study of Hanoi Vietnamese and ge

Vietnam national university, Hanoi University of languages and international studies Faculty of Post graduate studies

DOÃN MINH MÃO

A comparative acoustic study of Hanoi

Vietnamese and general American English

HA NOI – 2012

Vietnam national university, Hanoi University of languages and international studies Faculty of Post graduate studies

DOÃN MINH MÃO

A comparative acoustic study of Hanoi

Vietnamese and general American English

Supervisor: Pham Xuan Tho, M.A.

HA NOI – 2012

LIST OF TABLES

1 The first and second formant frequencies of all the subjects for 34

each vowel.

2 The values of the first and the second token of each sound 47

produced by each speaker.

3 The average values of F1 and F2 for each vowel as spoken by 53

ten speakers

Figure Title

researcher.

subject.

produced by another subject.

produced by a subject.

produced by another subject

produced by a subject The spectrogram of [a] is on the left, and of [ăi] is on the right.

the right.

F2 by the first 4 subjects.

dialect

for each monophthong as spoken by ten speakers

eight English monophthongs The scales are marked in Hz, arranged at Bark scale intervals

female speakers

produced by female speakers

LIST OF FIGURES

TABLE OF CONTENTS

STATEMENT OF AUTHORSHIP i

ABSTRACT iv

ACKNOWLEDGEMENT v

LIST OF TABLES vi

LIST OF FIGURES vii

TABLE OF CONTENTS viii

Chapter 1: INTRODUCTION 1

1 Rationales 1

2 Scope of the research and the research questions 3

Chapter 2: THE REVIEW OF LITERATURE 5

2.1 The articulatory description of Hanoi Vietnamese monophthongs 5

2.2 The acoustic description attempts 10

2.3 Characterizing vowel qualities with the acoustic properties 16

2.4 General American English 24

2.4.1 The traditional description 24

2.4.2 The acoustics of GA 27

Chapter 3 RESEARCH METHODOLOGY 30

3.1 The subjects 30

3.2 The stimuli 30

3.3 The recording process 31

3.4 The analysis process 32

Chapter 4: FINDINGS AND DISCUSSION 34

4.1 The acoustics of Hanoi Vietnamese monophthongs 34

4.1.1 [ɛ̆] and [ɛ] 35

4.1.2 [ɤ] and [ɤ̆] 40

4.1.3 [a] and [ă] 43

4.1.4 Regression analysis

48

4.1.5 Charting the formants of Hanoi Vietnamese monophthongs 51

4.2 The monophthongs of Hanoi Vietnamese and General American English in comparison Chapter 5 CONCLUSION 62

5.1 The main findings on the acoustics of Hanoi Vietnamese monophthongs 62

5.2 The monophthongs of Hanoi Vietnamese and General American English in comparison 63

5.3 The limitations of the study and suggestions for further research .64

REFERENCES 66

Appendix 1: Phiếu chấp thuận tham gia vào nghiên cứu 68

Appendix 2: The stimuli 69

58

Chapter 1: INTRODUCTION

1 Rationales

The ultimate aim of this research is to achieve a cross languagecomparison between the acoustic properties of Hanoi Vietnamesemonophthongs and General American English monophthongs Thefindings of the accomplished study are significant, from both thelinguistic and pedagogical perspectives

Ladefoged states firmly that, “The best way of describing vowels is not

in terms of the articulations involved, but in terms of their acousticproperties.” (2003, p.104) A considerable amount of space of this thesis

is devoted to the researcher’s analysis of the monophthongs, or purevowels (Wells, 1962, p.1) of Vietnamese, Hanoi dialect Aside from afew studies conducted overseas, which have important limitations to beaddressed, which are discussed in details in the Review of Literature ofthis thesis, there has been no attempt to study the vowel acoustics of therecognized standard Vietnamese so far

The literature on Vietnamese vowel acoustics has been mainly concernedwith the description of the sounds from the views of articulatoryphonetics The investigations conducted by Nguyễn (1998), and Đoàn(2000) are typical examples These studies examined the behaviors ofthe vocal organs involved in the articulatory process when a particularsound is being produced This method, while having the advantage of

forwards ideas which remain an approximation to the truth Ladefoged and Johnson (2011, p.197) comment,

Traditional articulatory descriptions are often not in accord with the actual articulatory facts For well a hundred years, phoneticians have

been describing vowels in terms such as high versus low and front versus back To some extent, they have been using these terms as

labels to specify acoustic dimensions rather than as descriptions of actual tongue positions Phoneticians are thinking in terms of acoustic fact, and using physiological fantasy to express the idea.

Acoustics offers sufficient tools for explaining the vowel qualities Theproduction of a speech sound involves firstly the vibration of the vocalcords, which produces sound waves It involves secondly theperformance of the vocal tract, which can be changed into variousshapes, as a filter, under the acoustic impedance Vowel sounds arecharacterized acoustically by formants, which are frequency regions ofhigh energy concentration corresponding to the pass bands of the throatand mouth cavities (Wells, 1962, p.1).Therefore, instead of onlystudying a particular sound from the outside, rather subjectively, byobserving with eyes, trying to set up a collection of its articulatoryfeatures, there should be a rigorous description method where everydimension of a sound as its nature is measured and displayed objectively

on the screen of an electronic device

The analysis, carrying out appropriately, would result in an acousticvowel chart, representing accurately the linguistic aspects of Hanoi

Vietnamese monophthongs, which serves as a valuable source ofreference for cross language comparison.

The pronunciation of General American English and of HanoiVietnamese are acknowledged as the reference accents of English andVietnamese respectively As a result, from the pedagogical aspect, thefindings of the research are of highly practical values in teaching thepronunciation of one language to learners of the other language

2 Scope of the research and the research questions

The study first examined the quality of the pure vowels in HanoiVietnamese The frequencies of each of the first two formants of eachmonophthong (F1, F2) were investigated on the acoustic spectrographs,generated from the speech analyzer program PRAAT

The results obtained from the analysis were then compared with theresults of a recent research in the monophthongs of General AmericanEnglish, conducted by Clark, M J, Hillenbrand, J, et al (1995)

The research is aimed at answering two questions:

1) What are the acoustic properties characterizing Hanoi Vietnamese monophthongs?

2) What are the common and distinctive features between the relativepositions of the monophthongs in Vietnamese and General AmericanEnglish on the formant charts?

Chapter 2: THE REVIEW OF LITERATURE

2.1 The articulatory description of Hanoi Vietnamese

monophthongs

There have been considerable attempts to give a description of the vowelsystem of Hanoi Vietnamese, impressionistically and acoustically Thispart of the review of literature is concerned firstly with the set ofVietnamese monophthongs in Hanoi dialect, the description of which hasgenerated a great amount of debate among phoneticians I shall then give

an examination of the second set, being described with fair consistency

As mentioned above, the vowel inventory of Vietnamese includes somemonophthongs that have been described consistently in the literature;they also have transparent orthographic representation: i/i/, u/u/, ô/o/,o/ɔ/, ê/e/, e/ε/, a/a/ However, for some other monophthongs,

orthographically realized by ư, ơ, â, and ă, there are important

conflictions in description For example, Lindau (1978), as cited in Matt

(2009) describes ư as high back unrounded, while Thompson (1965)

insists that it is high central unrounded, or as and high central, asproposed by Pham (2003) Hwa-Froelich (2002), as cited in Matt (2009),

puts forward the suggestion that ư that includes /ɯ/ and /ʊ/, is

characteristically employed to denote a high back unrounded and alower-high back rounded vowel, respectively Lindow (1978) has

identified ơ as being back unrounded, /ɤ/ or /ʌ/, while according to

Thompson (1965), it should be represented by /ə/

According to Matt, Alina, and Alison (2009) there are two reasons for

the inconsistency in the description of ư and ơ Firstly, the acoustic

distinction between lip-rounding and the backness of the tongue is notclear The traditional analysis of spectrogram cannot convincinglydifferentiate the characteristics because of the almost similar, or evenequal acoustic properties (Ladefoged, 2011) The second reason is thedifferent goal behind the phonetic and phonological descriptions of thevowels concerned Phonetic descriptions, the goal of which is to provide

a description of the vowels’ features as being realized in spoken speech,are concerned with the articulatory or acoustic features of the vowels.Phonological descriptions, on the other hand, are concerned with thevowels’ structure and function in relation to each other in a system.Naturally, different goals of the studies conducted have resulted in theinconsistency

As mentioned earlier, there are two other Vietnamese vowels, which

have been identified with conflicting features The vowels realized by â and ă are traditionally described as “short”, low central However, there

has been a great amount of debate surrounding whether these vowels are

short counterparts of ơ and a respectively, which are long vowels of

similar quality, or they are short vowels with distinct vowel qualities.One of the ultimate goals of the current study is to provide a systematicdescription of the quality of Hanoi Vietnamese pure vowel inventory;therefore, it shall not be concerned with the vowel duration

Thompson (1965) is among the references of highest citation frequency.

In his rather comprehensive account of the Vietnamese language, a fineamount of space has been devoted to the vowel system of Hanoi dialect

According to Thompson (1965), the dialect’s vocalic system consists oftwo sub-systems of upper vocalics, which includes six vowels and threesemivowels, articulated relatively high in the mouth, and lower vocalics,which includes five vowels and one semivowels, articulated relativelylow The table below gives further details on this

The Vocalic System, Thompson (1965, p.12)

It can be made clearer from this table what Thompson (1965) hasillustrated The upper vocalics includes three positions, being relativelydistinctive from each other: front, back unrounded, and back rounded Ahigh vowel, an upper-mid vowel, and a semivowel occupy each of thepositions He emphasizes that there are no vowels

that occur at the final position Further description of the uper - vocalicsvowels are provided as follows.

/i/ is proposed here as a high front or central unrounded vowel It is

lower high central before final ch, nh, as in ích, be useful, and lính, soldier Before ê, p, m in the same syllable, it is an upper high front vowel Examples are provided as in biết, miệng, kíp, tìm, which means

know, mouth, be urgent, and search for respectively It is lower high

front elsewhere in the same syllable

/e/ is characterized as being upper mid front or central, unrounded It is

upper mid central before final ch, nh; and after [i] before [w, p, m, t, n]

in the same syllable, which is “slightly lower before [w]” (p.30)

Examples given include ếch, bênh, hiểu, tiếp, which respectively means

frog, defend, understand, and receive in English The vowel is upper-mid

/o/ is identified as being upper mid back rounded It is higher mid before

[j, w], as in tôi, (I), rồi, (be already accomplished), cô, (aunt), lỗ, (hole), and is mid strongly centralized after [u], as in buồn, (be

sad), quốc, (country), tuổi, (age), chuột, (rat) Finally, it is upper mid

elsewhere, that is, before [p, m, t, n]

/ε/ is proposed to be lower mid front unrounded There is little variationwhen the sound is realized in different contexts

/ɔ/, is much like that of /ε/, maintaining its quality when beingdistributed differently The vowel is described as lower mid backrounded

/a/ is characterized as a lower low front unrounded vowel

Đoàn (2000) has proposed the largest vowel inventory of Vietnamese,with thirteen monophthongs, including /i/, /e/, /ɛ/, /ɛ̆/, /ɯ/, /u/,/o, /ɔ/, /ɔ̆/, /ɤ/, /ɤ̆/, /a/, and /ă/ The author did not attempt to describethese vowels in terms of how they are articulated, as articulatoryphoneticians have often done Instead, qualities of all the vowels aredescribed firstly in terms of their timbre The timbre is then explained asbeing high (bổng), mid-low (trầm vừa), and low (trầm) The table belowillustrates how Vietnamese monophthongs are distinguished from eachother in terms of their timbre, according to the author (p.191)

-High category: /i, e, ɛ, ɛ̆/

Mid-low category: /ɯ, ɤ, ɤ̆,a, ă/

Low category: /u, o, ɔ, ɔ̆/

However, it is not clear from the explanation what the vowels are high,mid-low, and low in terms of If that is concerned with pitch, thereappears to be confusion between the vowel quality and the pitch atwhich they are produced Acoustic studies of vowels have demonstratedthat the pitch of vowels, as perceived by listeners, is decided by thefundamental frequencies of the sound waves producing that vowel (F0),and has practically no effect on the vowel quality.

There are four pairs of Vietnamese vowels, which according to the study, differentiated by duration These include /ɛ̆/ and /ɛ/, /ɔ̆/ and /ɔ/, / / and /ă/, /ɤ/ and /ɤ̆/ It is maintained that these four pairs of vowel have the same quality, and are in long-short opposition (p.195)

2.2 The acoustic description attempts

Matt et al (2009) carried out an exploration of the Vietnamesemonophthongs produced by a small group of native speakers from bothnorthern and southern Vietnam The researchers also attempted toprovide a comparison between the native production and those made byAmerican adult learners The goals of the study are significant Themethod of conducting the study, however, is problematic In order toeliminate the anatomical differences among participants, the

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Fabricious (1973) has been employed in the study This method has beenseverely attacked by modern phoneticians.

Johnson (2005) pointed out that, “Talkers may differ from each other atthe level of their articulatory habits of speech This, in itself, wouldsuggest that perception may not be able to depend on vocal tractnormalization to “remove” talker differences by removing vocal tractdifferences” (p.19) Johnson et al (1993) goes further:

The presence of individual differences in speech production also complicates matters for vocal tract normalization Though normalization research has usually focused on male/female differences in vocal tract size and shape, vocal tracts - even within genders - come in lots of different sizes and shapes Talkers apparently adopt different (possibly arbitrarily different) articulatory strategies

to produce the “same” sounds Thus, accurate recovery of the talker’s articulatory gestures would not completely succeed in “normalizing” speech (P.20)

The second problem of the method is in its scale The study wasconducted on too small a scale so as to provide a conclusive support forthe researchers’ claims in the discussion of the findings According to theresearchers,

Native speaker participants included 3 Northern dialect speakers (1 female, 2 males) and 1 Southern dialect speaker (female) All were originally from Vietnam and had been living in an English-speaking country for 6 to 26 years They ranged from 42 to 64, and all had experience teaching Vietnamese as a foreign language to adults.

Firstly, the number of participants selected is too small, and is thereforestatistically insignificant This can be attributed to the authors’ reliance

on the normalization method adopted, as mentioned before Secondly,while the qualities of Vietnamese vowels have been recognized as beingsubstantially varied from dialect to dialect in realization, there is noindication that the subjects were screened for dialect, and very littleinformation is provided about the dialects of the speakers The presentresearch represents the researcher’s attempt to address these limitations.(see Chapter 3 for further details)

Srihari and Nguyen (2004) is another attempt to describe the Vietnamesevowel characteristics employing spectrograms analysis In order to makedecision on the set of vowels for the recording process, the authorsfollow the work of Thompson (1965, 1987), closely, claiming that thereare eleven monophthongs in the Vietnamese vowel system (Hanoidialect), which are /i, ɯ, u, e, γ, o,

ε, ɔ, ɐ, a, ɑ

The vocalics systems (Thompson, 1987, as cited in Srihari and Nguyen, 2004)

Making a comparison with the system that Mai, Vu, and Hoang (2008) proposed, considerable differences could be spotted In the latter account, it is suggested that there are 13 pure vowels in the system, and noticeably, there is not an existence of / ɑ/, characterized as a low, back, unrounded vowel, as Srihari and Nguyen (2004) maintain In addition, these authors support the claim that /γ, o, ε/ have three counterparts differing just in terms ofduration, which are /ɤ̆/, /ɔ̆/, and /ɛ̆/ This is a part of the inconsistentdescription of the Vietnamese vowel inventory, as mentioned earlier.Even Thompson (1987) has departed from his previous proposal made inThompson

(1965), with regards to the existence of /ɑ/ As a result, deciding on a set

of eleven monophthongs has posed a threat to the validity of thefindings

The aims of the study, as stated by its author, are to provide “a preliminary quantitative description of formant values for F1 and F2 for each vowel and plot the vowel chart of Vietnamese ” (p.2) However, what has made it even more problematic, again, is the scale of the research The subject of the study, as described, is “a 24-year-old native male speaker of Hanoi dialect, the standard dialect of Vietnam The speaker can speak English fluently but not well -trained in phonetics.” (p.2) This problem also occurred in the previous

study There are anatomical differences among speakers of a certainlanguage; therefore, selecting one subject for examination would notprovide findings which are representative of the population Given thatthe author would carry out an analysis on the qualitative aspects of thevowels in question, the conclusion on the acoustics of the vowels of alanguage being drawn from the analysis of the recording of a singlespeaker of it is seriously questionable Ladefoged (2003) pointed outthat, “The fact that data has been measured correctly does not show thatthere are no problems with the speakers When looking at the formants

of a group of people you should check whether any one speaker isdifferent in any way from the others.” (p.129)

The vowels of five speakers of Banawa, Ladefoged (2003, p.129)

The ellipse in the figure encloses four stressed [e] vowels of a speaker.

As can be seen, the first formant values of his [e] are distinct from those

of the other speakers This speaker, therefore, has produced this sound in

a way that is significantly different from the others This deviation,according to Ladefoged (2003), cannot be ascribed to some anatomicalfactor such as a very small vocal tract size This is because the othervowels produced by him are similar to those made by the rest of thespeakers The author’s suggestion is that, “if you find a speaker whopronounces a word in a significantly different way, you should leave thispart of the data out when providing diagrams of the vowel qualities ofthe language, noting, however, that there are speakers who deviate fromthe general pattern.” (p.129)

The second problem with the currently reviewed study involves the set

of words containing the vowels chosen for recording

The word list containing the vowels in question, Srihari and Nguyen (2004, p.3)

The /t-/ context is not the best choice According to Ladefoged (2011,p.199), a stop closure will cause the vowel’s first formant (F1) to risefrom a low position As a result, the accuracy of the formant valuescalculated might be affected It is suggested in a number of the studies(James et al., 1995; Broadbent & Ladefoged, 1957; Wells, 1962;Ladefoged, 2011) that a word list of the /h-d/ context would provide thebest spectrograms, as /h/ has almost no effect on the formants of theadjacent vowels in the same syllable.

2.3 Characterizing vowel qualities with the acoustic properties

The current study is inspired by Ladefoged’s (2003) firm statement that, “the best way

of describing vowels is not in terms of the articulations involved, but in terms of their acoustic properties ” (p.104) In this section we shall take a closer look at the acoustics

of vowels.

The different sounds of language are physically characterized with fourdimensions, which are the fundamental frequency, the amplitude, theduration, and the formants distribution of the sound wave The fourcorresponding perceptual dimensions are pitch, loudness, length, andquality

The current study has not investigated the amplitude and thefundamental frequency of vowels, being primarily concerned with thespectral distribution of the pure vowels The measurements of the vowelduration have been investigated insofar as they distinguish the

pairs of vowels having been described with inconsistency in articulatoryphonetics.

Articulatory phonetics describes how a vowel is articulated, in terms ofthe behaviors of the articulators, but there has not been a term todescribe the difference between the quality or timber of one vowel andanother vowel Among the dimensions of the complex sound wavesproduced by the human vocal cords, we need to consider carefully thespectral distribution of the component frequency A speaker canpronounce a vowel on any pitch within the range of his voice withoutchanging its identity Ladefoged (2003) provides a prime example:

I can say the vowels in heed, hid, head, had on a low pitch, when the vocal folds are vibrating about 80 times a second, and then I can say them again with vocal folds vibrating 160 times a second The pitch of my voice will have changed, but the vowels will still have the same quality I can also say any vowel loudly or softly The quality, the factor that distinguishes one vowel from another, remains the same when

I shout or talk quietly (p.31)

The differences among vowels are often compared with the differentinstruments The same note can be played on a guitar, a violin, or apiano This can be done as the sound is produced at the same rate ofrepetition of a special component wave, i.e, the fundamental frequency.What is interesting here is that, the quality of the music produced by oneinstrument will be different from that of any other This is due to thedifferences in the amplitude as well as the frequency of the componentwaves The quality of a vowel differs

from that of another in plainly the same way Irrespective of the pitch onwhich a vowel is produced, the quality will stay unchanged.

A popular way that phoneticians describe the acoustics of the humanspeech sounds is using the tube models The current research isprimarily concerned with the monophthongs (of Vietnamese), so themodels can be conveniently summarized as follows

The air in a bottle will be set vibrating when the body of air at the top of

it is blown across Naturally, the note that is produced as a result ofblowing the air at the bottle top will depend on the size and the shape ofthe bottle The more the volume of air inside is increased, the lower willthe produced note be This is due to the fact that the smaller body of airwill vibrate more quickly than that of a larger one, having a higherfrequency of resonance

When a vowel is being produced, it is the vocal tract that acts like abottle, with the size and the shape being constantly altered If for abottle, the air inside is set in vibration when blowing across the air at thetop, for the vocal tract it is the pulses of the air from the vocal folds.What makes the tract different from the bottle is its very complex shape,which can be constantly changed due to the movements of the relatedorgans Conveniently, phoneticians often consider the body of air in thethroat to be the first tube, and that in the mouth to be the second one.The resonances of the vocal tract are called the formants, whichcorrespond to the basic frequencies of the vibrations of the air in thevocal tract Therefore, the formants of a

sound are the properties that directly depend on the size and the shape ofthe tract, both the front and the back part of the cavity They are largelyresponsible for the characteristic quality of the vowel My vowel [i] in

the Vietnamese word hi is characterized by formants around 380, 2200,

and 3200 Hz

Figure 1: The spectrogram of the author’s pronunciation of [i] in hi

When my vowel [i] is produced, a damped wave is generated, andalways with these approximate basic frequencies It is this set ofcomponents that allow us to distinguish [i] from the other vowels Eachvowel is associated with a different shape of the vocal tract, resulting inthe different component basic frequencies (the formants) being producedwhen the body of air inside vibrates

The traditional articulatory descriptions of vowels show a closerelationship with the frequencies of the formants of the vowels As theacoustic studies of vowels have demonstrated, the frequency of the firstformant (F1) is responsible for the vowel quality of being high or low,and that of the second formant effects the degree of frontness orbackness, as described in articulatory phonetics This can be moreclearly illustrated with a formant chart of English vowels taken fromJohnson (2011), as follows.

A formant chart showing the frequency of the first formant on the ordinate plotted against the second formant on the abscissa, by Johnson (2011, p.197)

As it can be seen from the chart, in comparison with the first formantfrequency of [i], the first formant of the vowel [a] increases noticeably It

is also apparent that, in these vowels, as the height of the vowelsdecreases, their F1 increase As for the second formant frequencies, it ismarkedly higher for the front vowels than in the back vowels Briefly, inrelation to the descriptions in articulatory phonetics, the degree offrontness or backness varies proportionally with the frequency of thesecond formant (F2), and the height of the vowels varies inversely withthe first formant frequency (F1)

In the previous reviews of the two studies on the vowels of Vietnamese,

I have questioned the conclusion of the authors, because of the scale onwhich the research was conducted, ranging from one to four nativespeakers as the subjects It is now that this can be further justified AsLadefoged (2001) has pointed out, we can describe the vowel qualities

of a particular vowel, produced by a particular speaker by calculating thevalue of the first and the second formant However, due to theanatomical differences among speakers, the precise formant frequenciesthat the vocal folds’ vibrations generate might be comparativelydifferent For instance, a speaker with a bigger head will have a largerresonating cavity, which results in his comparatively lower formants,both the F1, and F2 In contrast, a vowel produced by a speaker with asmaller vocal tract will have formants with relatively lower formantfrequencies Ladefoged (2001), concludes that, “In order to represent thevowels of a language, we need to show the average values of theformants ”

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and “the most useful representation of the vowels of a language is a plot showing the average values of formant one and formant two for each vowel as spoken by a group of speakers.” (p.39)

In order to arrange the Vienamese monophthongs investigated in thisstudy later so as to reflect both the acoustic dimentions as well as thetongue position as articulatory phoneticians wish, it is essential to take acloser look at a plotting approach, which has been widely employed inrecent studies

The answer to this plotting question is in the arrangement of thefrequency scales Let us take the descriptions of the two vowels /i:/and /u:/ in consideration, from the articulatory phonetics’ perspectives

When producing /i:/, as in the English word heed, the speaker’s tongue is

pulled up and forward from the rest position so that it is front and high in

the mouth When producing /u:/, as in Who’d, however, the position of the tongue is still high, roughly as high as that of /i:/, but now it is pulled

backward

These facts have a close relation to the formant frequency While thetongue position for /i:/ is high, the frequency of the first formant, F1, islow It is a front vowel, and its second formant frequency is high Forthat of /u:/, the tongue position is still high Correspondingly, the firstformant, F1, is high However, what makes it different from /i:/ is thesecond formant As a back vowel, the second formant of /u:/, F2, isnoticeably higher than that of /i:/ As a result, the values of the firstformants of vowels indicate the tongue’s behaviors

22

Consequently, in order to plot the vowels on a chart to indicate theformant frequencies as well as the approximation of the tongue position,the scale of F1 must represent the decreasing values For the secondformant, as the traditional phonetic diagram shows the front vowels onthe left, and the back vowels on the right, the scale indicating F2 valuesmust go from right to left, in order to represent the quality of being front

or back Below is a diagram, with the scales arranged as discussedaforementioned

A combined acoustic and articulatory representation of some of the vowels of

American English., Johnson & Ladefoged (2011, p.218)

2.4 General American English

2.4.1 The traditional description

One of the ultimate goals of the current study is to compare thedistribution on the formant chart between Hanoi Vietnamesemonophthongs and General American English monophthongs; thissection is devoted for an examination of the concept of GeneralAmerican English (GA) and its monophthongs in literature

Generally, phoneticians are united surrounding the definition Thepronunciation of American English is traditionally divided into theEastern pronunciation, which includes New York City and New England,Southern, which stretches from Virginia to Texas and the southwards,and General, which includes all the remaining General American, GA,

is comparable with RP in Britain A speaker of GA is a person whoseaccent does not tell which region of the country he comes from Put itanother way, GA is described as having no characteristics of a specificregion in the United States Just as RP, sometimes referred to as Queen’sEnglish, or BBC English, GA is often referred to as Network English “It

is the standard model for the pronunciation of English as an L2 in parts

of Asia, and parts of Latin America.” (Gimson, 2008, p.84)

According to Wells (1982), there are two major systemic differencesbetween British RP and GA Firstly, in RP, there are three diphthongs/iə/, /eə/, /ʊə/ which cannot be found in GA Instead, in

GA, there are sequences of short vowel plus /r/, such as in heard, fare

/bɪrd/, /fer/ Secondly, there is no /ɒ/ in GA In RP hot is pronounced

as /hɒt/, but in GA, it will become /hɑ:t/ This is true withvirtually all the other cases of /ɒ/ in RP, such as in bottle, cot, pot, spot

However, Gimson (2008) also points out that a limited subset of GA

has /ɔ:/, for example, across, gone, often, cough, orange, porridge

In terms of the lexical occurrence, the differences are in words of RPhaving /ɑ:/, while in GA, they become /æ/ Gimson (2008) also stressesthat this commonly happens in the context before a voiceless fricative, or

before a nasal followed by another consonant For example, RP past

[pɑ:st] is GA [pæst]

Bellow is the further examples of the comparison between RP and GA vowels, provided by Gomez (2012, p.12)

Change of vowel /ɒ/ to /ɑ:/. and /ɔ:/,

Regarding the diphthongs, which is not the primary concern of thecurrent study, the differences between the two systems are varied Themost noticeable change is the shift from / əʊ/ in RP to that of /oʊ/ in GA,

such as in home, [həʊm] of RP, and [hoʊm] GA As Gomez (2012) has

pointed out, the shift is concerned with the change of the mid centralunrounded vowel /ə/ to the close-mid back rounded

vowel /o/ in the first vowel of the diphthong This shift, according to theauthor, is considered to be systematic He offers several examples of thischange in the table below (p.14)

2.4.2 The acoustics of GA

Hillenbrand et al (1995) conducted a study of the acoustic properties of

GA The vowels /ɪ, i, e, ɜ, æ, a, ɔ, o, ʊ, u, ʌ, ɝ/ in /h-v-d/ syllables,produced by 45 men, 48 women, and 46 children were recorded

The majority of the participants, (87%), were born and raised inMichigan’s Lower Peninsula, the southeastern and southwestern parts ofthe state of Michigan The remaining were from other parts of upperMidwest, including Illinois, Wisconsin, Minnesota, northern Ohio, andnorthern Indiana In order to increase the homogeneity of the sample,ensuring that they all speak GA, a procedure of selecting the subjectsfrom the larger group, described by the researchers as being “anextensive screening procedure” was conducted The key

part of the procedure was a careful assessment of dialect It focused on the subjects’ production of /a/ - /ɔ/ distinction.

The formants of F1-F4 were measured from the LPC spectra Below arethe average F1-F2 formant charts of pure vowels as produced byAmerican men and women

The average formant frequencies of the pure vowels produced by

American men (Hillenbrand et al., 1995, p.1304)

The average formant frequencies of pure vowels produced by American

women (Hillenbrand et al., 1995, p.1304)

It is clear from the charts that, although the absolute values of theformant frequencies between men and women are significantly different,due to the anatomical differences between two sexes, the relativepositions of the monophthongs on the charts, indicating how thesevowels are articulated, are strikingly similar

Chapter 3 RESEARCH METHODOLOGY

3.1 The subjects

Ten female speakers of Hanoi Vietnamese were chosen in a procedure asfollows First, 20 females aged from 15 to 25, who claimed to have spentmost of their life, since being born, in Hanoi were chosen to take part in

a recording process They were then asked to read a short piece ofVietnamese scripts (Appendix 2) After that each of the recordings wasplayed back to all the subjects, except for the person producing it Thelisteners were asked to judge whether each piece of speech soundstypically Hanoi Vietnamese, giving a score ranging from one to ten, with

ten being most typical, and one being the least Ten of the twenty

subjects who achieved the highest scores were selected This procedureensured the high homogeneity among the subjects

3.2 The stimuli

Thirteen Vietnamese monophthongs were investigated In differentaccounts proposed by different authors, as discussed in the review ofliterature, the number of monophthongs in the system is a matter of

controversy Whether the pairs of vowels, as in anh (brother) and xe (vehicle), ong (bee) and oong, ha and hay (interesting), hơ and hân

should be described as two vowels in long-short opposition, having thesame vowel qualities, represented by /ɛ̆/ and /ɛ/ /ɔ̃/ and /ɔ/ ,

distinct quality, or /ɛ̆/, /ɔ̃/, /ă/, and /ɤ̆/ are allophones of the longercounterparts, have divided linguists The current research treated them asbeing distinct from each other, either in terms of the qualities orduration; therefore, the quality of these thirteen vowels, which is thelargest inventory proposed so far, were investigated Based on the results

of the acoustic analysis of F1 and F2, the controversial matters would bediscussed in the section of findings and discussion To record thesubjects’ production of these vowels, /i, e, ɛ, ɛ̆,ɯ, u, o, ɔ, ɔ̆,ɤ, ɤ̆,a,ă/were divided into two sets The first set, including /i, e, ɛ, ɯ, u, o, ɔ,

ɤ, a,/ are represented by the corresponding letters in the Vietnamese

alphabet, i, ê, e, ư, u, ô, o, ơ,

a. The second set, including, /ɛ̆/, /ɔ̆/, /ɤ̆/, and /ă/, as described by

linguists, have limited distribution Therefore, they are realized in four

words, anh, óc, ân, ay respectively.

3.3 The recording process

The subjects were required to say the given words and letters two times

to the Shure PG27USB microphone, with the relevant specificationsinformation provided by the producer as follows:

December 19, 2011) This connectivity method allowed the researcher toconduct convenient digital recording anywhere that a computer can betaken along In addition, the integrated pre -amp with Microphone GainControl allows the control of input signal strength, meaning there is norequirement of an amplifier This is especially suitable for phoneticfieldwork, where it is commonly impossible to take the speakers of aspeech community to a laboratory for recording.

The microphone was set up with a personal computer with thespecifications as follows:

 Processor: Intel Core i5 2.5 GHz

 Ports 4 x USB 2.0; FireWire; VGA port; S-video port

 Screen resolution: (max) 1,280 x 800