SUMMARY OF THESIS TEACHERS CORRECTIVE FEEDBACK ON THE PRONUNCIATION OF ENGLISH FRICATIVES AND AFFRICATES BY NON-ENGLISH MAJOR FRESHMEN

PART A: INTRODUCTION
I. Statement of the Problem and Rationale of the Study
Of four English skills, speaking plays an integral part in every school’s
English curriculum in Vietnam. In the process of improving speaking skills, many
learners face the problem of pronunciation. In fact, according to many foreigners,
Vietnamese learners can speak English; however, not many of them have
intelligible English pronunciation so that they can be understood easily in direct
communication with foreigners (Duong, 2009). In her view, the low level of
communicative competence of learners is directly attributed to their deficiencies in
pronunciation, not vocabulary and grammar. This is the justification of why
teaching pronunciation needs to be given priority.
For two years working at the Diplomatic Academy of Vietnam (DAV), the
researcher has realized that most of her first-year students show few improvements
in pronunciation after two semesters although they are required to speak English in
all English lessons. In other words, their frequent mistakes tend to be maintained as
the first days they entered the Academy. Through direct observation in many
English speaking lessons at DAV, of 24 English consonants, two alveolar
fricatives /s, z/, two alveo-palatal fricatives /ʃ, ʒ/ and affricates /ʤ, ʧ/ have been
identified as the most common pronunciation mistakes of the researcher’s students.
They have also been more confirmed after considerable discussion with many teachers
at DAV. For instance, most of the students tend to pronounce the word social as /
ˈsəʊsl/ instead of /ˈsəʊʃl/, or television as /ˈtelɪvɪzn/ instead of /ˈtelɪvɪʒn/.
The fact remains that learners with poor pronunciation at the segmental level
are not always at an advantage. Yates (2002, p.1) believes, “we often judge people
by the way they speak, and so learners with poor pronunciation may be judged as
incompetent or lacking in knowledge.” That is the reason why the researcher finds it
necessary to teach her first-year students how to pronounce individual sounds
correctly because it will serve as a foundation for better speaking competence in the
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next three years. In order words, they need to start with individual sounds before
moving on other complicated aspects of speech such as intonation, stress, etc.

With regard to the coursebooks used by freshmen in English speaking
lessons at DAV, namely Let’s talk 2 in the first semester and Let’s talk 3 in the
second semester, they do not consist of any sort of pronunciation work on
individual sounds. Instead, they contain a variety of speaking activities for the
purpose of developing students’ oral communication skills and fluency. However,
in many situations, when a student delivers a talk, mistakes like /ˈsəʊsl/ and /
ˈtelɪvɪzn/ seem not to be perceived. Furthermore, those who are less likely to notice
such pronunciation mistakes are non-English majors.
From the researcher’s viewpoint, the problem lies in the fact that students do
not receive adequate feedback from the teacher on their pronunciation performance.
In other words, they need to be assisted by the teacher to realize their problems. It
is suggested that Teacher’s Corrective Feedback (TCF) can be used to help learners
perceive and discard what is unacceptable or inappropriate from their interlanguage.
Considering the benefits TCF can bring to learners of English, the researcher wants
to determine if TCF can solve her students’ pronunciation problems in terms of the
six English consonants /s, z, ʃ, ʒ, ʤ, ʧ/ in English speaking lessons where
pronunciation work is not included.
Last but not least, research into TCF on pronunciation mistakes in English
speaking lessons at university level in Vietnam is quite small in number. All the
aforementioned reasons have motivated the researcher to conduct this quasi-
experimental research on Teacher’s Corrective Feedback on the pronunciation
of English fricative and affricate consonants by non-English major freshmen at
the Diplomatic Academy of Vietnam.
II. Aim and Objectives of the Study
The study aims at helping non-English major freshmen at DAV improve their
pronunciation of the six consonants /s, z, ʃ, ʒ, ʤ, ʧ/.
To be specific, the primary objectives of the study are as follows:
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• To examine the effect of TECF on the pronunciation of the six consonants /s, z,
ʃ, ʒ, ʤ, ʧ/ by non-English major freshmen at DAV;

• To investigate the experimental students’ opinions about TECF on their
pronunciation of the six consonants /s, z, ʃ, ʒ, ʤ, ʧ/ after the experimental
period.
III. Research Hypothesis and Research Questions
III.1. Research Hypothesis
A hypothesis is constructed for the purpose of achieving the aim of the study:
H
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: Non-English major freshmen who receive TECF make more significant
improvements in their pronunciation of the six consonants /s, z, ʃ, ʒ, ʤ, ʧ/ than
those who do not receive TECF.
If the above hypothesis is fully accepted, the following null hypothesis will
be obviously rejected or vice versa:
H
o
: There is no difference in the pronunciation of the six consonants /s, z, ʃ,
ʒ, ʤ, ʧ/ between non-English major freshmen who receive TECF and those who do
not.
In order to identify which hypothesis will be accepted, the first research
question, posed in Section III.2, needs to be satisfactorily answered.
III.2. Research Questions
Based on the aim and objectives of the study, two questions were formulated
and needed to be satisfactorily answered:
(1) What is the difference that Teacher’s Explicit Corrective Feedback brings about
in the pronunciation of the six consonants /s, z, ʃ, ʒ, ʤ, ʧ/ by non-English major
freshmen at the Diplomatic Academy of Vietnam?
(2) What are the experimental group’s opinions about Teacher’s Explicit Corrective
Feedback on their pronunciation of the six consonants /s, z, ʃ, ʒ, ʤ, ʧ/ after the
experiment period?
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IV. Scope of the Study
Initially, corrective feedback as stated in the research title is, in fact, confined
to Explicit Corrective Feedback.
Regarding English fricative consonants, the study focuses on two English
alveolar fricatives /s, z/ and two alveo-palatal fricatives /ʃ, ʒ/. When it comes to
English affricate consonants, they are /ʤ, ʧ/. Only issues concerning the pronunciation
of these sounds are taken into consideration.
Finally, it should be noticed that 36 non-English major freshmen in the class
KT40B at DAV were involved in the study but only 34 students were eligible to
become its main subjects.
V. Methodology
A quasi-experiment was adopted in this study so as to test the research
hypothesis stated in Section III.1. First, based on a pre-test of the six consonants /s,
z, ʃ, ʒ, ʤ, ʧ/ administered to 36 students in the class KT40B, 34 participants were
selected and assigned into two groups, control and experiment. Then, they
participated in a ten-week experiment, in which a 30-minute instruction on the six
consonants /s, z, ʃ, ʒ, ʤ, ʧ/ was delivered to both groups at the beginning of every
lesson. Afterwards, they got involved in a number of the same speaking activities;
however, only the experimental group received TECF on their pronunciation
mistakes regarding /s, z, ʃ, ʒ, ʤ, ʧ/. Meanwhile, the control group got feedback on
the content of their statements or arguments. After the experimental period, both
groups sat for a post-test (version of the pre-test). The pre-test and post-test scores
were analyzed by means of paired-samples t-tests to find out the answer to the first
research question. Besides, a short written questionnaire was employed as the
supplementary instrument to investigate the experimental students’ opinions about
TECF on their pronunciation mistakes regarding /s, z, ʃ, ʒ, ʤ, ʧ/ after the
experiment.
VI. Significance of the Study:
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The study would be of great benefit for two reasons:

Initially, the research outcome could be used as evidence of the impact of
TECF on Vietnamese university students’ pronunciation. As for English teachers in
general and English teachers at DAV in particular, they could base themselves on the
results of the paper to make informed decisions on whether TECF should be
encouraged or not. In fact, if there exists a positive link between TECF and students’
pronunciation of the six consonants /s, z, ʃ, ʒ, ʤ, ʧ/, it can bring about a significant
change in many English speaking lessons at colleges and universities, where
pronunciation work is not included.
In addition, this study can serve as a reliable source of related literature and a
basis for other researchers, who share an interest in the topic, to start their future work
from.
VII. An Overview of the Rest of the Paper:
PART B: DEVELOPMENT
CHAPTER I: LITERATURE REVIEW
CHAPTER II: METHODOLOGY
CHAPTER III: RESULTS
CHAPTER IV: DISCUSSION
PART C: CONCLUSION
PART B: DEVELOPMENT
CHAPTER I: LITERATURE REVIEW
I.1. The Importance of Pronunciation Teaching and Learning
I.2. Aspects of Pronunciation
I.3. The Aim of Teaching Pronunciation: Intelligibility
I.4. General Description of Consonants and English Consonants
I.5. English Fricative Consonants
I.6. English Affricates
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I.7. Previous Studies on Vietnamese Learners’ Pronunciation of the Six English
Consonants /s, z, ʃ, ʒ, ʤ, ʧ/
I.8. Teacher’s Corrective Feedback

I.8.1. Definition of Teacher’s Corrective Feedback
I.8.2. Types of Teacher’s Corrective Feedback
I.9. Teacher’s Explicit Corrective Feedback
I.10. Theoretical and Empirical Background on TECF
I.11. Research Gap
CHAPTER II: METHODOLOGY
II.1. Context of the Study
The study was conducted at the Diplomatic Academy of Vietnam, which is
located at 69 Chua Lang Street, Dong Da, Hanoi.
On average, freshmen and sophomores at DAV spend about nine hours per
week on learning English, which is divided into four sessions. Each session lasts for
135 minutes and only focuses on one English skill.
Generally, students at DAV are divided into two major groups, namely,
English majors and non-English majors. English majors refer to students who enroll
in the discipline of English and non-English majors are from five disciplines of
International Relations, International Laws, International Economics and
International Communication. Both groups have to complete an English foundation
course in the first three semesters. In the fourth semester, there is a difference in the
learning programs of two groups. English majors have sessions of Phonetics,
Grammar, Pragmatics, etc. Meanwhile, non-English majors participate in the ESP
programs.
With regard to speaking skills, the teaching materials for non-English major
freshmen are two books Let’s Talk 2 (used in the first semester) and Let’s Talk 3
(used in the second semester). These books include a variety of interesting and
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innovative topics that encourage students to develop their oral communication
skills. Nevertheless, it is noticed that there is no room for teaching pronunciation in
the two books.
It cannot be certain that students who sail through the university examination
for group A1 and D1 are good at English pronunciation because the English test

they take is in the form of a written one. Furthermore, as mentioned in the first
chapter, many non-English major freshmen at DAV are observed to make a lot of
pronunciation mistakes when speaking; meanwhile, the teaching materials skip the
English pronunciation part. Therefore, it is necessary to improve their current
situation of learning English in general and English pronunciation in particular.
II.2. Study Design
The researcher decided to choose the following quasi-experimental design:
First, a pre-test was administered to 36 students in the class KT40B for three
purposes:
• To select the main subjects of the study. To be specific, the subjects having
much lower or higher scores than the rest of subjects (in statistics, they are
called “outliers”) would be ruled out from the sample. In other words, the
main subjects, who later were assigned to the experimental and control
group, were roughly at the same pronunciation level of English alveolar
fricatives, alveo-palatal fricatives and affricates.
• To assign the subjects to the experimental and control group.
• To compare with the post-test to find out the answer to the first research
question.
After that, in ten weeks, the intervention (TECF) was administered to the
experimental group whereas there was no intervention in the control group.
Finally, after ten weeks, both groups sat for a post-test whose structure was
similar to that in the pre-test. The method of scoring is also the same. The pre-test
and post-test scores of both groups were used for comparison so that the answer to
the first research question can be found.
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Besides, a short written questionnaire was used as the supplementary
instrument to explore the experimental students’ evaluative opinions about TECF
after the experiment period.
This quasi-experimental design is feasible for the researcher to conduct the
present study. The results of the study were presented in numerical expression (e.g.,

test scores) and then analyzed by trustworthy and powerful statistical computer
software. To be specific, in this study, the link between the pre-test and post-test
scores of both groups was brought to light by paired-samples t-test with the
assistance of the computer software SPSS version 16.0 (Statistical Package for
Social Science), which is widely-used for statistical analysis.
II.3. Selection of the Main Subjects for the Study
To select the main subjects of the study, a test on the six English
consonants /s, z, ʃ, ʒ, ʤ, ʧ/ was administrated to 36 students in the class KT40B. To
be specific, the subjects having much lower or higher test scores than the others
would be ruled out from the sample. In other words, the main subjects who later
were assigned to the experimental and control group were roughly at the same
pronunciation level of the above-mentioned sounds.
In statistics, outliers are cases that have data values very different from the
data values of the majority of cases in the data set. The way a subject having the test
score that differs significantly from the other test scores in the sample are ruled out
is similar to the way an outlier is found.
Two outliers were found. They are case 7 scoring 79 points and case 30
scoring 61 points. Hence, for the purpose of the study, the two students were ruled
out from the sample. The main subjects of the study are 34 students in the class
KT40B.
II.4. Assignment of Subjects to the Experimental and Control Group
After the main subjects were selected, they were assigned to the
experimental and control group based on their pre-test scores. The process is
clarified as follows:
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 The subjects were placed in matched pairs and closely matched pairs for
random assignment.
 Coins were flipped for both matched and closely matched pairs. If the coin
came up heads, the subject was assigned to the experimental group; if tails,
the control group

Though the assignment of subjects in seven closely matched pairs to the
experimental and control group, decided by flipping a coin, cannot guarantee that
both groups are equated on the most important variable – prior achievement level, it
is confident to say that both groups are closely matched on this variable. When “the
intervention and comparison groups are very closely matched in key
characteristics”, valid results are likely to be produced (Jon Baron, 2007, p.5). In
this way, threat to the internal validity of the study can be reduced.
II.5. Instruments for Data Collection
 Instrument One: Pre-test and Post-test
The pre-test was designed mainly based on Vietnamese learners’ common
pronunciation problems regarding the six consonants /s, z, ʃ, ʒ, ʤ, ʧ/ as mentioned
in the Literature Review chapter. It consists of 100 test items and is divided into two
main parts, namely paper-and-pencil and sound production. The maximum score
that a student can get is 100 points.
The paper-and-pencil part contains ten questions. In each question, the test
takers had to choose one out of four words, which has the same sound as the
underlined part of the given one. Each correct answer is rated one point. The
maximum score that a student can get is 10. The time allowance for the test is 10
minutes, excluding the time of delivering the test paper. The whole class KT40B sat
for the paper-and-pencil test at the same time on the same day. The test was
administered under the surveillance of the researcher and another English teacher at
DAV to make sure that no student could copy the others’ answers.
When it comes to the sound production part, there are 90 test items regarding
the six consonants /s, z, ʃ, ʒ, ʤ, ʧ/. First, the test takers were required to read aloud
30 individual words which contain target sounds in the final position. Afterwards,
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the examinees had to read aloud three dialogues and four passages at normal speed.
In these dialogues and passages, there were 60 test items regarding the six
consonants /s, z, ʃ, ʒ, ʤ, ʧ/ prepared by the researcher in advance. Before reading
aloud, they were given several minutes for preparation. Scoring is straightforward

with points counted only for the individual items being evaluated (Marianne, Donna
and Janet, 1996). The total score of the sound production part is 90 points. Correct
pronunciation of each test item will score one point. With regard to some words that
appear in the part more than once, one point will be equally divided based on the
frequency of the word.
After the experimental period, the post-test, the version of the pre-test, was
used again to measure the performance of two groups. The most important thing is
that in the post-test, the test items were reordered in order to make a more objective
evaluation of the students’ performance. The steps of administering the post-test
were the same as the pre-test. The post-test took place in May.
 Instrument two: Audio-recording
Audio-recording was utilized in the process of scoring because (1) the use of
a small recording machine was assumed to reduce the subjects’ anxiety during the
recording process; hence, they were likely to produce more natural English sounds
and (2) the digital sound quality might be better than that captured by regular
cassette recorders.
 Instrument three: Written questionnaire
A short written questionnaire with three-point likert scale was administered
to the students in the experimental group to explore their evaluative opinions about
TECF after the experiment.
The steps of administering the questionnaire were also well-prepared. First,
before the questionnaire was distributed, the experimental students were made to
feel relaxed and comfortable to give their true responses because their own opinions
were for study, not for any other reasons. Next, they were asked to show their
opinions about seven statements in the questionnaire in three ways. If they agreed
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with a statement, they would mark in the Agree column with a check. If they
disagreed with a statement, the Disagree column would be chosen with a check. If
they had no idea about the issue mentioned, a check would be put in the No opinion
column. Furthermore, the questionnaire was written in Vietnamese to make sure

that the respondents did not have any difficulty in understanding the statements in
the questionnaire. Last but not least, the data collected from the questionnaire was
analyzed carefully and presented in detail in the next chapter. The result of the
questionnaire would be helpful in shedding light on the second research question.
II.6. Instrument for Data Analysis
In this study, paired-samples t-tests were used to examine the difference in
the test scores between two groups and, therefore, to identify if the experimental
group could generally better their English fricative, alveo-palatal and affricate
sound production after ten weeks of receiving TECF. In order to find out the answer
to the first research question, steps were carried out as follows:
First, though the experimental and control group were assigned to be closely
matched in their prior achievement level of English fricatives, alveo-palatal
fricatives and affricates, the process of random assignment, as mentioned in Section
II.4, cannot avoid a difference between the two groups. Hence, the pre-test scores of
both groups were calculated to measure the initial difference between them before
the experiment. Then, the gain scores of two groups were compared to find out the
effect of TECF after the experiment. The gain score of each subject in both groups
was calculated by subtracting the pre-test score from the post-test score for
comparison. Finally, the impact of TECF was checked again by comparing the post-
test scores of both groups. After the aforementioned steps, the researcher could
come to a conclusion about whether the possible difference between two groups
after the experimental period was statistically significant.
II.7. Treatment to the Experimental Group and Control Group
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At the beginning of every lesson, Ms. Julia, a native English teacher at BBC
English Center, delivered a 30-minute instruction on the six consonants /s, z, ʃ, ʒ, ʤ,
ʧ/ to both the control and experimental group. In the first week, students in both
groups were offered instructional videos illustrating the correct pronunciation of the
six target consonants. Afterwards, they took it in turns to practice pronouncing these
sounds at segmental and word level. These activities aimed at helping students gain

basic knowledge about the correct pronunciation of the six target consonants. From
week 2 to week 11, both groups worked on these sounds at word level. The
vocabulary items for each week were chosen under the condition that they
contained the six target consonants and were related to the topic of the speaking
lesson at the Academy. When students were confused about the pronunciation of a
certain sound in the six ones, instructional videos were played again to help them.
After 30 minutes of instruction, based on the given vocabulary items, Ms.
Julia led students to the topic of the speaking lesson. Then, both groups participated
in the same learning activities designed beforehand. The learning activities will be
clarified later in this paper.
With regard to the experimental group, it was divided into two subgroups.
The experimental subgroup 1 had eight members and the experimental subgroup 2
had nine members. Each subgroup was instructed by a teacher.
Similarly, the control group also had two subgroups. However, concerning
the two students who were not eligible to become the main subjects of the study
(case 7 and case 30), they cannot be rejected from the classroom as can be done in
the laboratory setting. Therefore, the researcher decided to assign them to the
control group, but these two students would not sit for the post-test. This led the
control subgroup 1 to have nine members (including case 7) and the control
subgroup 2 to have ten members (including case 30).
It should be noticed that the researcher did not participate in the teaching
process. Instead, she observed the learning process in the classroom.
 The experimental group
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In an attempt to reduce the complexity of intelligibility, as discussed in the
Literature Review chapter, during the experimental period, the instructors provided
17 experimental students with TECF on their problems related to the six consonants
/s, z, ʃ, ʒ, ʤ, ʧ/, namely sound omission, sound substitution, and sound redundancy.
Feedback provided by the instructors was operationalized as pronunciation-focused
TECF. It was used to elicit the correct form from students who made pronunciation

mistakes in their utterances. If TECF resulted in incorrect output, further
metalinguistic feedback was employed to help students produce correct output on
their own.
 Control Group
Meanwhile, no TECF about such pronunciation mistakes was directed at
those in the control group. In all activities, the instructors in the control group
provided corrective feedback on the content of the students’ statements or
arguments, e.g. Your arguments need more evidence, right? and vocabulary, e.g. In
this case, you can use the word “sufficient”.
II.8. Integration of Pronunciation Targets into the English speaking lessons
 Activity 1 – Picture description
 Activity 2 – Story telling
 Activity 3 – Group discussion
a. Problem-solving
b. Debate topics
CHAPTER III: RESULTS
III.1. Comparison of the Pre-test and Post-test Scores
III.1.1. Comparison of the Pre-tests Scores of Both Groups
A paired-samples t-test was conducted by SPSS software to compare the pre-
test scores of two groups. The output is: There was a very small difference (.08)
between two groups prior to the ten-week experimental period. The p-value, labeled
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as Sig.(2-tailed) in the first row, is .508, which is much greater than .05. Hence,
there was no statistically significant difference between the control and
experimental groups at the alpha level of .05. It can be inferred that both groups,
before the treatment period, were more or less at the same starting point.
III.1.2. Comparison of the Gain Scores of Both Groups after the Experiment
The output is: The mean gain of the experimental group is much greater than
that of the control group (6.38 compared to 2.20). The p-value, labeled as Sig.(2-
tailed), is much lower than .05. As a result, the difference between the mean gains

achieved by two groups was statistically significant at the .05 level. The higher
mean gain obtained by the experimental group is the result of the experimental
treatment.
III.1.3. Comparison of the Post-test Scores of Both Groups
The output is: The mean of the control group is lower than that of the
experimental group with the mean difference of 3.88. The positive obtained t value
(11.736) with 16 degree of freedom and the p-value of .000 (<.05) indicate that the
difference between two groups was significant and the experimental group
outperformed the control group.
Conclusion: After the ten-week experiment, there was a significant difference
between the experimental and control group in terms of English fricative and
affricate sound production. Though both groups made certain progresses in their
pronunciation after ten weeks, the improvements made by the experimental
group who received TECF was significantly greater than that made by the
control group who did not receive TECF.
III.2. The Experimental Group’s Opinions about TECF on Their
Pronunciation of the Six English Consonants /s, z, ʃ, ʒ, ʤ, ʧ/.
The results of the questionnaire indicate that almost all the participants in
the experimental group showed positive opinions about TECF which was
implemented in a period of ten weeks. In other words, they acknowledged the
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positive impact of TECF in teaching pronunciation of English fricative and affricate
consonants in English speaking classrooms.
CHAPTER IV: DISCUSSION
IV.1. Discussion of Both Groups’ Pronunciation Gains Scores and Post-test
Scores after the Experimental Period
IV.2. Discussion of the Experimental Group’s Opinions about TECF on Their
Pronunciation of the Six Consonants /s, z, ʃ, ʒ, ʤ, ʧ/.
IV.3. Recommendations for the Application of TECF in English speaking
lessons

The current study first showed that the role of TECF is relatively important
for pronunciation learning because students need to receive the teacher’s corrective
feedback to produce intelligible sounds on their own (doing output practice), so that
their pronunciation mistakes can be reduced (learners’ control over the already-
internalized declarative knowledge, which promotes the transition from declarative
knowledge to procedural knowledge). In this respect, the researcher wants her
students to continue to receive TECF from every teacher they encounter throughout
their academic journeys. The researcher hopes that through TECF, not only
pronunciation mistakes in terms of the six consonants /s , z, ʃ , ʒ, ʤ, ʧ/ but also
pronunciation mistakes relating to other English sounds will be easily overcome by
the students. Furthermore, the researcher has come to realize how important TECF
is to her students at DAV. When the textbooks do not include any sort of
pronunciation work and there is a concern that students’ pronunciation mistakes
will be fossilized if they are not corrected by the teacher, it is necessary to integrate
TECF into different English speaking activities.
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CHAPTER V: CONCLUSION
I. Conclusion
As a quasi-experimental design, this study aims to help DAV non-English
major freshmen overcome their pronunciation problems in terms of the six
consonants /s, z, ʃ, ʒ, ʤ, ʧ/. The experiment was carried out on a class of 36 first-
year non-English majors who were learning English as a foreign language at DAV.
The theoretical background for the study was totally presented and discussed
in the Literature Review chapter, in which the positive impacts of TECF in L2
learning were pointed out as the results of the previous studies. Then, in the
Methodology chapter, the study design was clarified. The study took a pre-test and
post-test design as the main measure to explore the first research question set out
before the experiment. In this design, the control group took the conventional
teacher’s feedback in English speaking classes while the experimental group
received pronunciation-focused TECF. Pair-samples t-tests were used to compare

the pre-test and post-test scores gained by both groups. In Chapter III and IV, the
significant findings of the study were presented and discussed in detail to determine
the answers to the research questions. As for the first research question, the results
of the experiment indicate that there was a significant improvement in the post-test
made by the experimental group. Furthermore, the experimental subjects’ feedback
to the questionnaire was an affirmative answer to the second research question. That
is, most experimental students had positive opinions about TECF. They
acknowledged that they were capable of acquiring the pronunciation of the six
consonants /s, z, ʃ, ʒ, ʤ, ʧ/ through TECF and that TECF became an effective way
to develop their pronunciation in the future. In short, the greatest impression gained
from this questionnaire was that the respondents found TECF very useful and
recognized its positive impact on their pronunciation. Furthermore, most of the
experimental students apparently benefited a lot from TECF (in fact, in the post-
test, their pronunciation mistakes regarding the six consonants /s, z, ʃ, ʒ, ʤ, ʧ/ were
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reduced). Thus, there is evidence to suggest that the TECF would be a valuable
complement to the existing methodologies.
II. Limitations of the Study
The first limitation is the sample size of the study. The fact remains that the
quasi-experimental design in this study was on a limited number of subjects (a class
of 36 students) and only 34 students were eligible to become the main participants.
It would be unlikely to ensure that the findings of the study would be always true to
other subjects in other learning contexts. This means that the subjects in this study
could not be representative of a larger population. Though the statistical results of
the pre-test and post-test analyzed by means of t-tests revealed that the experimental
students who received TECF made more improvements in pronouncing the six
consonants /s, z, ʃ, ʒ, ʤ, ʧ/ than those who did not, the subjects’ reaction to TECF
may vary in different contexts.
Furthermore, it must be remembered that this experiment was carried out in a
real-life classroom, not in a laboratory. The lack of consideration of other possible

factors is also a critical limitation of this research paper. Although most of the
participants claimed that they grew more confident in their sound production of the
six target consonants after the experimental period, it could hardly be generalized
that only the use of TECF positively impacted these improvements. There might be
other factors such as motivation, beliefs, individual interests, etc. contributing to
these achievements. This definitely raises the question of internal and external
validity of the test. This limitation makes it hard to generalize the findings.
The final limitation of the study is attributed to the limited time for the
experimental treatment with TECF. Hence, it is advisable that TECF continues to be
given to overcome this deficit. From a research perspective, the control and
experimental treatments need to be continued for a longer period of time to see if
the effect of TECF still remains and if the experimental group makes further
progress. Unfortunately, the researcher's limited time did not permit anything else.
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III. Recommendations for Further Studies
Since this study was just conducted on a small sample size with a ten-week
experimental period, it was impossible for the researcher to firmly establish the
effect of TECF on student’s sound production. Thus, further research needs to be
done with a larger sample size and for a longer time so that the results would
become more valid. In addition, more studies should be carried out to consider the
impact of TECF on other English consonants as well as other aspects of
pronunciation such as intonation and sentence stress. Moreover, further research
should be conducted on students at other educational establishments so that TECF
would be more confirmed as an effective way for teaching English pronunciation in
English speaking classrooms. Finally, in order to bring the present study to higher
reliability and validity, it should be carried out under true experimental conditions.
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