An Analysis of Vietnamese EFL Students’ Pronunciation of English Affricates and Nasals

English learners in Vietnam may have many difficulties when pronouncing English, mainly Nasals and Affricates since English has been their second most used language. There are many factors which lead to this problem like their mother tongue, their study environment, and a lack of knowledge about English phonology and phonetics. This assignment analyzes the problems in English’s Affricates and Nasals pronunciations experienced by Vietnamese EFL students. Data were collected and analyzed from many Vietnamese students including tips and techniques to improve each different pronunciation of Affricates and Nasals. This research will hopefully widen knowledge for those who want to improve their pronunciation of Affricates and Nasals and establish more information which could be able to be developed in the English phonology and phonetics systems in Vietnam.


The Background
English is one of the most commonly used languages all over the world as it is used in many different contexts.In Vietnam, Project 2020 by the Vietnamese government has launched in-service training programs for ELT teachers at elementary, middle and high schools (Bui Phu Hung, 2016).Also, several schools in Ho Chi Minh City, Vietnam, have introduced content-based instructional programs (Bui Phu Hung & Tran Thi Hai, 2016).However, Vietnamese students' pronunciation errors are still an issue of concern (Graceffo, 2010).Pronunciation errors may be caused by the teacher's application of inappropriate teaching methods, interference of L1 (Shak, Lee, & Stephen, 2016).
Pronunciation plays a significant role in real-life communication as it reflects the speakers' identities and the communities which they belong to (Seidlhofer, 2001).Good pronunciation also helps students get academic achievements and graduates get accepted for vacancies and promotions at work.However, Shak, Lee and Stephen (2016) identified many problems in Vietnamese students' pronunication of English.
This study is aimed to analyze Vietnamese EFL students' errors in pronunciation of affricates and nasals in English and suggests methods of teaching and learning pronunciation for Vietnamese students at low levels of proficiency as Vietnamese language does not have consonant clusters or a glide from one consonant to another as in English affricates (Huynh Trang Nguyen & Dutta, 2017) and Vietnamese EFL students do not pronounce English final consonants clearly enough (Duong Thi Nu, 2009).

Research Questions
1).Which of the English affricates and nasals do Vietnamese EFL students make most pronunciation errors in?
2).Do Vietnamese students make more errors in pronoucing affricates or nasals?

Definition
An affricate is a consonant that begins with a stop and ends with a fricative.These two sounds are generally homorganic (Roach, 2001).In other words, the places of articulation of these two sounds should be close.In English, there are two affricates, known as /tʃ/ and /dʒ/ in which the first consonant is an alveolar plosive, produced with a plosion, and the second is a post-alveolar fricative, produced with friction (Roach, 2001).Clark, Yallop & Fletcher, 1995, p. 65) believes that "There is almost always some degree of air turbulence (and hence friction) at the release of a stop.This is normally of such short duration that it counts as part of the release burst of the stop itself.However, when the release is strongly frictional and is extended in duration, it can be identified as a separate fricative phase of the articulation.A single complex segment of this kind, in which the articulators release an occlusion through a controlled fricative phase, is known as an affricate or affricative."(Clark, Yallop, & Fletcher, 1995, p. 65) Pisoni & Remez (2005, p. 195) identify that the English affricates are an acoustic segment of oral alveolar stops and post-alveolar fricatives which are incorporated perceptually into a single phonological entity.This acoustic sequence is produced by the oral alveolar stop followed by the post-alveolar fricative.As a consequence, the English affricates contain acoustic cues for both stops and fricatives.That means the acoustic cues for the English affricates /tʃ/, /dʒ/ are more complicated than those of the English fricatives /ʃ/, /ʒ/.
/tʃ/ is a voiceless consonant in which /t/ glides from alveolar to post-alveolar position, both /t/ and /ʃ/ are both voiceless consonants so /tʃ/ is a voiceless consonants./tʃ/ can be spelled in the initial position, medial position and final position, usually spelled "ch".Nonetheless, /dʒ/ is a voiced consonant which can be spelled in initial position, medial position and final position as "j".The following table can illustrate this point.Misra (2000, p. 78) identifies that /tʃ/ is a voiceless alveolar palatal affricate.This sound can be produced when the tip of the tongue touches the alveolar ridge or just behind it.For example, the sound /č/ in the word "church".
It may be noticed that the production of this sound is similar to that of /š/, except that the airflow is initially stopped and then released slowly.On contrary, /dʒ/ is a voiced alveolar palatal affricate.The sound /ǰ/ in the word "judge" is produced in a similar fashion as /č/, except that it is a voiced sound.The fricative /s/, /z/, /š/,/ž/ and the affricates /č/ and /ǰ/ are together called as sibilants, as they produce a typical hissing noise.

Arguments on Affricates
There have been arguments on analyzing affricates.First is the one-phoneme analysis, as explained in the first part, affricates /tʃ/ and /dʒ/ are phonetically composed of a plosive followed by a fricative, and it is possible to treat each pair /tʃ/ and /dʒ/ as a single consonant phoneme, so we called this the one-phoneme analysis.Second is two-phoneme analysis, affricates are also be treated as composed of two phoneme each, respectively, /t/ followed by /ʃ/ and /d/ followed by /ʒ/ , all of which are established as independent phonemes in English.As in the two-phoneme analysis, it is possible to say that an affricate is composed of two phonemes each -/t/ plus /ʃ/ or /d/ plus /ʒ/ respectively.If we adopt the two-phoneme analysis, the words "church" and "judge" would be composed of five phonemes each instead of the three-phoneme that result from the one-phoneme analysis.However, most linguists prefer the two-phoneme analysis as it has one main advantage that if there are no separate /tʃ/ and /dʒ/ phonemes, then our total set of English consonants is smaller.Many phonologists have claimed that one should prefer the analysis which is the most "economical'' in the number of phonemes it results in (Roach, 2001, p. 122).
Phoneticians argue that the phonetic quality of the /t/ and /ʃ/ as in ("hutch" /hətʃ /and "watch apes" watʃ eps/) is different from realizations of /t/ and /ʃ/ in other contexts as in ("hush" /həʃ /or what shapes /wət ʃeps/).This argument is weak since there is no evidence for the existence of these phonetic differences.

Distribution of Affricates in English Words
The phonemes /tʃ/ and /dʒ/ are widely distributed like other consonants in all positions (initial, medial, final) while other combinations of plosives and fricative do not.However, several consonants like /r/, /w/, /j/, /h/, /ŋ/, /ʒ/ are generally accepted as phonemes despite not being free in distribution.If /tʃ/ and /dʒ/ are able to combine quite freely with other consonants to form consonant clusters, e.g., finally in "watched" / wɑtʃt/.However, such clusters do not exist in the initial position and are very limited in the final position.
The intuitions of native speakers may suggest that /tʃ/ and /dʒ/ are each "one sound".The problem is that discovering what native speakers feel about their own language is not easy.
Furthermore, when it comes to assimilation, affricates have more drastic type of co-articulation.Instead of "sharing" part of a sound, the merged sounds are pronounced as an entirely different sound.Two examples of assimilation occur when /t/ or /d/ precede the "y sound" /y/.

Definition
Hancock (2003) recognizes that the consonant sounds /m/, /n/ and /ŋ / are made by stopping the flow of air out of the mouth so that it goes through the nose instead.These three consonants are different because the air is stopped at different parts of the mouth.In particular, /m/, /n/ and /ŋ/ are bilabial, alveolar and velar in position of articulation respectively.Agreeing with Hancock (2003), Roach (2001, p. 58) further explains that the soft palate must be lowered for nasals to be produced.However, for all the other consonants and vowels, the soft palate is raised and air cannot pass through the nose.He adds air does not pass through the mouth; it is prevented by a complete closure in the mouth at some point.The three types of closure are: bilabial (lips), alveolar (the tongue blade against the alveolar ridge) and velar (the back of tongue against the palate).This set of places produces three nasal consonants /m/, /n/, and /ŋ/, which correspond to the three places of articulation for the pairs of plosives /p/ and /b/, /t/ and /d/ and /k/ and /g/.
Almost all nasals are continuants, where air comes out through the nose but not through the mouth, as it is blocked by the lips or tongue.Nasals are all voiced and never appear in pair as plosives, fricatives and affricates.

Characteristics of Nasals
Roach (2001, p. 58) asserts that /ŋ/ consonant is at velar and this consonant is different from /m/ and /n/, which it causes a lot of trouble for those who is not a native speaker as this consonant does not exist in some languages.
In addition, non-native English speakers' pronunciation of this consonant may be found unintelligible.While large number of languages make use of phoneme /ŋ/, many others lack this sound.However, few of the sounds commonly found among the phonemic inventories of the world's languages exhibit a more clearly definable distribution than that exhibited by /ŋ/.This distribution has two unrelated aspects.One is the striking areal distribution of the presence vs. absence of phonemic /ŋ/ among the languages of the world.The other striking aspect of phonemic /ŋ/ is its phonotactic distribution.That means it may not appear in all positions in the word, but rather confines itself to initial, medial, or final position, or some combination thereof.In the case of restriction of ŋ to non-initial position, this, too, has a relatively pronounced areal skewing among the world's languages.However, Vietnamese language has a consonant also called velar nasal occurs in all initial, medial and final positions (Kirby, 2011).

Previous Studies
There have been many studies on EFL students' pronunciation of English, but the studies by Dikilitaş & Geylanioğlu (2012), Duong Thi Nu (2009), Hassan (2014), Mirza (2015), Ohata (2004) and Zhang (2009) as they have been conducted in contexts where English is used as a foreign language.
Dikilitaş & Geylanioğlu ( 2012) conducted a study on 24 Turkish EFL adult students' pronunciation of English consonants and vowels.In this study, each of the participants was given 10 words for each sound.Their pronunciations were recorded and transcribed IPA alphabet and compared to the phonetic transcription in dictionaries.The Turkish participants were found having difficulties in pronuncing the target sounds, including /ŋ/.It is recommended from the study that students should be trained through concetualization theory to assist learners in forming an idea or principle of the target pronunciation lessons.
Duong Thi Nu ( 2009) studies the pronunciation mistakes of English fricatives and affricates made by Vietnamese students.The scope included both the manners and places of articulation of these consonants.She also suggested ways to improve EFL students' pronunciation of English: good teacher instruction, comparisons and contrasts of English and Vietnamese phonetic features and more controlled practice and language use.
Hanssan ( 2014) investigated Sudanese problems with pronunciation of English words.50 Sudanese students at University of Sudan of Science and Technology were involved as participants in the study.Their spoken English was observed, recorded and analyzed.These participants were also interviewed.A conclusion of the study is that interference of L1, differences between two languages, inconsistency of sounds and spelling were the main causes of English pronunciation problems.Mirza (2015) analyzed Lebanese EFL and EFL students' pronunciation mistakes.22 participants were included in the study.Tests and checklists were applied.The findings revealed that the participants made more mistakes with fricatives and affricates.Ohata (2004) examines phonological difference between English and Japanese.The study also discussed problematic areas of pronunciation for japanese learners of English.The author also figured out implications for L2 pronunciation teaching based on the contrastive analysis of the two languages.
Zhang ( 2009) analyzed common problems in Chinese EFL learners' pronunciation.The factors that led to these problems included L1 interference, learners' age, attitudes and their inadequate understanding of phonological and phonetic system of English.

The Pilot Study
5 students were voluntarily included in the pilot study and they were not included in the main study.They were given a text and were required to read the text loud.Their readings were recorded and then compared to available recordings, made by native-English speakers, accompanying the textbook.After the pilot study, the text was cut off to 200 words as the participants claimed that a long text would take them much time.

Participants
32 Vietnamese EFL students from different institutions of higher education located in Ho Chi Minh City were included in the study.Their age range was 18-23 and they were from different cities and provinces in Vietnam.They had all learned English at basic levels of education.

Instruments
References accompanied by recordings were read through by the researcher to be level-fit.Finally, an approximately 200-word elementary-level paragraph was chosen.Recorders were also used to record the participants' readings of the text.

Procedure
Firstly, an approximately 200-word paragraph was chosen among many textbooks with words containing affricates and nasals.The chosen paragraph was not commonly taught in Ho Chi Minh City, Vietnam.The paragraph was presented in a printed form.The participants were asked to read out loud the paragraph for a few times so they could be familiar with it.Afterwards, their readings were recorded and converted into MP3 format.
Secondly, the recorded readings were transcribed according to English phonetic symbols (Roach, 2001) by four Vietnamese EFL teachers one by another.These four teachers used the recording in accompaniment with the text as a reference for their checking.Then the recorded readings were checked through by a native-English teacher who had come to Vietnam 2 weeks before the implementation of this study.The participants' pronunciations of the affricates and nasals were labelled accuracy levels: high, intermediate, and low to mean the levels of identification of the phonemes.
Finally, the participants' pronunciation mistakes were summed up and discussed by all the checkers for a mutual agreement on the labels of accuracy.

Results and Discussions
32 recordings made by 32 the participants were analyzed with a focus on affricates and nasals at three main levels: high, intermediate and low.Table 4 and Table 5 illustrate this analysis of the participants' pronunciation of each word in the text.The statistics show the numbers and percentages of pronunciation levels of accuracy of the mentioned words.The analysis shows that the participants made more errors with the pronunciation of affricates than nasals.In particular, the affricates in the final position were often skipped or omitted by the participants.The participants also made more errors with the pronunciation of /ŋ/ than the other nasals.

General Conclusions
In conclusion, from many records collected, there are many mistakes at the way each EFL student pronounced.
Most EFL students mispronounced both /tʃ/ and /dʒ/ as they still did not know how to pronounce words that contain these phonemes.That was why the percentage of high accuracy in affricates arrived at 68.8% and the words "education" and "educationally" had the highest rate of low accuracy pronunciation (81.3%) in all 11 words that contain affricates.The participants, in fact, made the phonemes /t/ and /d/ in these words respectively instead.The interview revealed that they did not know this and their pronunciation of these words were influenced by their previous teachers.They also said that those words based on their spelling and did not really know the correct phonetic features.While in nasals, most words with /m/ and /n/ were pronounced correctly or clearly enough for listeners to hear and to understand, but the word "younger", with 37.5% of low accuracy, proved that /ŋ/ in nasals is mostly mispronounced.

Recommendations
There are many ways to improve student' pronunciations of affricates and nasals.As Szpyra-Kozlowska (2016) pointed out that "People with poor pronunciation often lack the confidence to speak up and try to say as little as possible.On the other hand, good pronunciation provides learners with the confidence to engage in conversations with other speakers of English, allows them to sound able and competent, and gives them a sense of achievement.It is an asset that cannot be underestimated.''Therefore, in order to improve their pronunciation, EFL students must check on themselves to be more confident in speaking and try to correct their pronunciation of affricates and nasals.In affricates, trying to distinguish the difference between /tʃ/ and /dʒ/, especially in some words like education and church, is relatively significant.In nasals, most EFL students are good at pronouncing /m/, /n/ in many and parent, but some might have a lack of pronouncing / ŋ / in some words like singer and English.

Table 3 .
Distribution of nasals in a word

Table 3
shows that /m/ and /n/ appear quite widely in a word, but /ŋ/ does not appear in the initial position.

Table 4 .
The analysis of affricates

Table 5 .
The analysis of nasals