a comparative acoustic study of hanoi vietnamese and general american english monophthongs = phân tích âm học so sánh hệ thống nguyên âm đơn tiếng việt hà nội và tiếng anh mỹ phổ thông

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 an

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

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

Supervisor: Pham Xuan Tho, M.A

HA NOI – 2012

LIST OF TABLES

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

each vowel

34

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

produced by each speaker.

47

ten speakers

53

LIST OF FIGURES

2 The effect of [ɲ] on [i] in inh and nhi, as produced by the

researcher

34

subject

38

produced by another subject

38

produced by a subject

39

produced by another subject

39

produced by a subject The spectrogram of [a] is on the

left, and of [ăi] is on the right

44

the right

45

F2 by the first 4 subjects

50

dialect

53

for each monophthong as spoken by ten speakers

54

eight English monophthongs The scales are marked in Hz,

arranged at Bark scale intervals

56

female speakers

57

produced by female speakers

58

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 [ɛ ̆] and [ɛ] 35

4.1.2 [ɤ] and [ɤ ̆] 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 58

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

Chapter 1: INTRODUCTION

1 Rationales

The ultimate aim of this research is to achieve a cross language comparison between the acoustic properties of Hanoi Vietnamese monophthongs and General American English monophthongs The findings of the accomplished study are significant, from both the linguistic 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 acoustic properties.” (2003, p.104) A considerable amount of space

of this thesis is devoted to the researcher’s analysis of the monophthongs, or pure vowels (Wells, 1962, p.1) of Vietnamese, Hanoi dialect Aside from a few studies conducted overseas, which have important limitations to be addressed, which are discussed in details in the Review of Literature of this thesis, there has been no attempt to study the vowel acoustics of the recognized standard Vietnamese so far

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

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 The production of a speech sound involves firstly the vibration of the vocal cords, which produces sound waves It involves secondly the performance of the vocal tract, which can be changed into various shapes, as a filter, under the acoustic impedance Vowel sounds are characterized acoustically by formants, which are frequency regions

of high energy concentration corresponding to the pass bands of the throat and mouth cavities (Wells, 1962, p.1).Therefore, instead of only studying a particular sound from the outside, rather subjectively, by observing with eyes, trying to set up a collection of its articulatory features, there should be a rigorous description method where every dimension 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 acoustic vowel chart, representing accurately the linguistic aspects of Hanoi

Vietnamese monophthongs, which serves as a valuable source of reference for cross language comparison

The pronunciation of General American English and of Hanoi Vietnamese are acknowledged as the reference accents of English and Vietnamese respectively As a result, from the pedagogical aspect, the findings of the research are of highly practical values in teaching the pronunciation 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 Hanoi Vietnamese The frequencies of each of the first two formants of each monophthong (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 the results of a recent research in the monophthongs of General American English, 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 relative positions of the monophthongs in Vietnamese and General American English 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 vowel system of Hanoi Vietnamese, impressionistically and acoustically This part of the review of literature is concerned firstly with the set of Vietnamese monophthongs in Hanoi dialect, the description of which has generated 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 some monophthongs 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, as proposed 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 a lower-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 not clear The traditional analysis of spectrogram cannot convincingly differentiate the characteristics because of the almost similar, or even equal acoustic properties (Ladefoged, 2011) The second reason is the different goal behind the phonetic and phonological descriptions of the vowels 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 the vowels’ structure and function in relation to each other in a system Naturally, different goals of the studies conducted have resulted in the inconsistency

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 systematic description 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 fine amount of space has been devoted to the vowel system of Hanoi dialect

According to Thompson (1965), the dialect’s vocalic system consists

of two sub-systems of upper vocalics, which includes six vowels and three semivowels, articulated relatively high in the mouth, and lower vocalics, which includes five vowels and one semivowels, articulated relatively low 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) has illustrated The upper vocalics includes three positions, being relatively distinctive from each other: front, back unrounded, and back rounded A high vowel, an upper-mid vowel, and a semivowel occupy each of the positions He emphasizes that there are no vowels

that occur at the final position Further description of the uper vocalics vowels 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 front elsewhere

/u/ is described as a high back rounded vowel Thomson (1965) emphasizes that “it tends to be upper high, but only before [m] and

[p]” (p.31), as in chụp (seize suddenly), chum (earthenware jar), and

it will be lower high elsewhere, as in núi, (mountain), mũ, (hat), tuổi,

(age)

/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 variation when the sound is realized in different contexts

/ɔ/, is much like that of /ε/, maintaining its quality when being distributed differently The vowel is described as lower mid back rounded

/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 describe these vowels in terms of how they are articulated, as articulatory phoneticians have often done Instead, qualities of all the vowels are described firstly in terms of their timbre The timbre is then explained as being high (bổng), mid-low (trầm vừa), and low (trầm) The table below illustrates how Vietnamese monophthongs are distinguished from each other 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, there appears to be confusion between the vowel quality and the pitch at which they are produced Acoustic studies of vowels have demonstrated that the pitch of vowels, as perceived by listeners, is decided by the fundamental 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 Vietnamese monophthongs produced by a small group of native speakers from both northern and southern Vietnam The researchers also attempted

to provide a comparison between the native production and th ose made by American adult learners The goals of the study are significant The method of conducting the study, however, is problematic In order to eliminate the anatomical differences among participants, the normalization method inspired by Watt and

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

Johnson (2005) pointed out that, “Talkers may differ from each other

at the level of their articulatory habits of speech This , in itself, would suggest that perception may not be able to depend on vocal tract normalization to “remove” talker differences by removing vocal tract differences” (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 was conducted on too small a scale so as to provide a conclusive support for the researchers’ claims in the discussion of the findings According to the researchers,

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 therefore statistically 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 being substantially varied from dialect to dialect

in realization, there is no indication that the subjects were screened for dialect, and very little information is provided about the dialects

of the speakers The present research 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 Vietnamese vowel characteristics employing spectrograms analysis

In order to make decision on the set of vowels for the recording process, the authors follow the work of Thompson (1965, 1987), closely, claiming that there are eleven monophthongs in the Vietnamese vowel system (Hanoi dialect), 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 of duration, which are /ɤ̆/, /ɔ̆/, and /ɛ̆/ This is a part of the inconsistent description of the Vietnamese vowel inventory, as mentioned earlier Even Thompson (1987) has departed from his previous proposal made in Thompson (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 the findings

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 certain language; therefore, selecting one subject for examination would not provide findings which are representative of the population Given that the author would carry out an analysis on the qualitative aspects

of the vowels in question, the conclusion on the acoustics of the vowels of a language being drawn from the analysis of the recording

of a single speaker of it is seriously questionable Ladefoged (2003) pointed out that, “The fact that data has been measured correctly does not show that there are no problems with the speakers When looking

at the formants of a group of people you should check whether any one speaker is different 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 anatomical factor such as a very small vocal tract

size This is because the other vowels produced by him are similar to

those made by the rest of the speakers The author’s suggestion is

that, “if you find a speaker who pronounces a word in a significantly

different way, you should leave this part of the data out when

providing diagrams of the vowel qualities of the language, noting,

however, that there are speakers who deviate from the 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 rise from a low position As a result, the accuracy of the formant values calculated 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 the best spectrograms, as /h/ has almost no effect on the formants of the adjacent 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 four dimensions, which are the fundamental frequency, the amplitude, the duration, and the formants distribution of the sound wave The four corresponding perceptual dimensions are pitch, loudness, length, and quality

The current study has not investigated the amplitude and the fundamental frequency of vowels, being primarily concerned with the spectral distribution of the pure vowels The measurements of the vowel duration have been investigated insofar as they distinguish the

pairs of vowels having been described with inconsistency in articulatory phonetics

Articulatory phonetics describes how a vowel is articulated, in terms

of the behaviors of the articulators, but there has not been a term to describe the difference between the quality or timber of one vowel and another vowel Among the dimensions of the complex sound waves produced by the human vocal cords, we need to consider carefully the spectral distribution of the component frequency A speaker can pronounce a vowel on any pitch within the range of his voice without changing 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 different instruments The same note can be played on a guitar, a violin, or a piano This can be done as the sound is produced at the same rate of repetition of a special component wave, i.e, the fundamental frequency What is interesting here is that, the quality of the music produced by one instrument will be different from that of any other This is due to the differences in the amplitude as well as the frequency of the component waves The quality of a vowel differs

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

A popular way that phoneticians describe the acoustics of the human speech sounds is using the tube models The current research is primarily concerned with the monophthongs (of Vietnamese), so the models 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 of blowing the air at the bottle top will depend on the size and the shape of the bottle The more the volume of air inside is increased, the lower will the produced note be This is due to the fact that the smaller body of air will vibrate more quickly than that of a larger one, having a higher frequency of resonance

When a vowel is being produced, it is the vocal tract that acts like a bottle, with the size and the shape being constantly altered If for a bottle, the air inside is set in vibration when blowing across the air at the top, 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 related organs Conveniently, phoneticians often consider the body of air in the throat 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, which correspond to the basic frequencies of the vibrations of the air in the vocal tract Therefore, the formants of a

sound are the properties that directly depend on the size and the shape of the tract, both the front and the back part of the cavity They are largely responsible 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, and always with these approximate basic frequencies It is this set of components that allow us to distinguish [i] from the other vowels Each vowel is associated with a different shape of the vocal tract, resulting in the different component basic frequencies (the formants) being produced when the body of air inside vibrates

The traditional articulatory descriptions of vowels show a close relationship with the frequencies of the formants of the vowels As the acoustic studies of vowels have demonstrated, the frequency of the first formant (F1) is responsible for the vowel quality of being high or low, and that of the second formant effects the degree of frontness or backness, as described in articulatory phonetics This can be more clearly illustrated with a formant chart of English vowels taken from Johnson (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 formant frequency of [i], the first formant of the vowel [a] increases noticeably It is also apparent that, in these vowels, as the height of the vowels decreases, their F1 increase As for the second formant frequencies, it is markedly higher for the front vowels than in the back vowels Briefly, in relation to the descriptions in articulatory phonetics, the degree of frontness or backness varies proportionally with the frequency of the second formant (F2), and the height of the vowels varies inversely with the 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 on which the research was conducted, ranging from one

to four native speakers as the subjects It is now that this can be further justified As Ladefoged (2001) has pointed out, we can describe the vowel qualities of a particular vowel, produced by a particular speaker by calculating the value of the first and the second formant However, due to the anatomical differences among speakers, the precise formant frequencies that the vocal folds’ vibrations generate might be comparatively different For instance, a speaker with a bigger head will have a larger resonating cavity, which results in his comparatively lower formants, both the F1, and F2 In contrast, a vowel produced by a speaker with a smaller vocal tract will have formants with relatively lower formant frequencies Ladefoged (2001), concludes that, “In order to represent the vowels

of a language, we need to show the average values of the formants”

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 this study later so as to reflect both the acoustic dimentions as well as the tongue position as articulatory phoneticians wish, it is essential to take a closer look at a plotting approach, which has been widely employed in recent studies

The answer to this plotting question is in the arrangement of the frequency 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 the tongue position for /i:/ is high, the frequency of the first formant, F1,

is low It is a front vowel, and its second formant frequency is high For that of /u:/, the tongue position is still high Correspondingly, the first formant, F1, is high However, what makes it different from /i:/

is the second formant As a back vowel, the second formant of /u:/, F2, is noticeably higher than that of /i:/ As a result, the values of the first formants of vowels indicate the tongue’s behaviors

Consequently, in order to plot the vowels on a chart to indicate the

formant frequencies as well as the approximation of the tongue

position, the scale of F1 must represent the decreasing values For

the second formant, as the traditional phonetic diagram shows the

front vowels on the left, and the back vowels on the right, the scale

indicating F2 values must 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 discussed aforementioned

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 the distribution on the formant chart between Hanoi Vietnamese monophthongs and General American English monophthongs; this section is devoted for an examination of the concept of General American English (GA) and its monophthongs in literature

Generally, phoneticians are united surrounding the definition The pronunciation of American English is traditionally divided into the Eastern 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 whose accent does not tell which region of the country he comes from Put it another way, GA is described as having no characteristics of a specific region in the United States Just as RP, sometimes referred to as Queen’s English, 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 differences between 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

with virtually 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 RP having /ɑ:/, while in GA, they become /æ/ Gimson (2008) also stresses that 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 the current study, the differences between the two systems are varied The most 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 central unrounded vowel /ə/ to the close-mid back rounded

vowel /o/ in the first vowel of the diphthong This shift, according to the author, is considered to be systematic He offers several examples of this change 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 in Michigan’s Lower Peninsula, the southeastern and southwestern parts of the state of Michigan The remaining were from other parts

of upper Midwest, including Illinois, Wisconsin, Minnesota, northern Ohio, and northern Indiana In order to increase the homogeneity of the sample, ensuring that they all speak GA, a procedure of selecting the subjects from the larger group, described by the researchers as being “an extensive 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 are the average F1-F2 formant charts of pure vowels as produced by American 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 the formant frequencies between men and women are significantly different, due to the anatomical differences between two sexes, the relative positions of the monophthongs on the charts, indicating how these vowels are articulated, are strikingly similar

Chapter 3 RESEARCH METHODOLOGY

3.1 The subjects

Ten female speakers of Hanoi Vietnamese were chosen in a procedure as follows First, 20 females aged from 15 to 25, who claimed to have spent most 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 of Vietnamese scripts (Appendix 2) After that each of the recordings was played back to all the subjects, except for the person producing it The listeners were asked to judge whether each piece of speech sounds typically 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 procedure ensured the high homogeneity among the subjects

3.2 The stimuli

Thirteen Vietnamese monophthongs were investigated In different accounts proposed by different authors, as discussed in the review of literature, 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 the same vowel qualities, represented by /ɛ̆/ and /ɛ/ /ɔ̃/ and /ɔ/ , / / and /ă/, /ɤ/ and /ɤ̆/ respectively, or they are vowels with

distinct quality, or /ɛ̆/, /ɔ̃/, /ă/, and /ɤ̆/ are allophones of the longer counterparts, have divided linguists The current research treated them as being distinct from each other, either in terms of the qualities or duration; therefore, the quality of these thirteen vowels, which is the largest inventory proposed so far, were investigated Based on the results of the acoustic analysis of F1 and F2 , the controversial matters would be discussed in the section of findings and discussion To record the subjects’ 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 specifications information provided by the producer as follows: