D
US-China Foreign Language, ISSN 1539-8080
April 2012, Vol. 10, No. 4, 1098-1105
DAVID
PUBLISHING
Exploring Relationship Between Students’ Vocabulary Breadth
and Their Reading Proficiency∗
Preawpan Pringprom
Bangkok University, Bangkok, Thailand
The two main purposes of this research are: (1) to examine students’ vocabulary breadth and (2) to explore the
relationship between students’ vocabulary knowledge and their English reading proficiency. Subjects were 81
undergraduate students at Bangkok University studying EN112 in the second semester of academic year 2010 as
one of the required courses. The 2,000, 3,000, and 5,000 VLT (Vocabulary Levels Test) bilingual version
(English-Thai) was employed to measure the subjects’ vocabulary breadth. A multiple-choice-question-format RCT
(Reading Comprehension Test) was used to assess the subjects’ reading proficiency. Descriptive statistics were
utilized to find means and standard deviations. Pearson correlation was used to analyze the relationship between the
scores of the RCT and the scores of the VLT. The results indicate that the subjects’ vocabulary knowledge is
inadequate to comprehend any English written texts, and there is a strong correlation between the subjects’
vocabulary breadth and their English reading proficiency.
Keywords: vocabulary breadth, reading proficiency, vocabulary and reading proficiency
Introduction
Vocabulary knowledge could be regarded as having two primary dimensions: breadth and depth (QIAN,
1999; Wesche & Paribakht, 1996). Vocabulary breadth refers to how many words learners know whereas
vocabulary depth concerns how well a particular word learners know and be able to use it (Nation, 2006).
QIAN (1999) clarified vocabulary knowledge in his study that:
Breadth of vocabulary knowledge is defined as vocabulary size, or the number of words for which a learner has at
least some minimum knowledge of meaning. Depth of vocabulary knowledge is defined as a learner’s level of knowledge
of various aspects of a given word, or how well the learner knows this word. (p. 283)
From teaching experiences, the author has found that vocabulary is a big issue which concerns our
students’ English acquisition and development in all four skills. Vocabulary seems to be very problematic to
the majority of Bangkok University students who must study English as required courses but rarely use it in
their daily lives. This may be the reason that their vocabulary knowledge is very limited and goes nowhere
comparing to numbers of years they had studied English in the school.
∗
Acknowledgements: The author would like to extend her sincere gratitude to anonymous reviewers. The author appreciates Mr.
Willard Van De Bogart for his kind proofreading of this paper and also the Language Institute teachers who helped validating the
research instruments. Besides, the author would also like to thank the students for their helpful participation in the study. Finally,
the author is grateful to Professor Norbert Schmitt for giving her permission to make a bilingual version of the VLT as well as
researchers and authors whose articles were referred to in this paper.
Preawpan Pringprom, Ph.D., assistant professor at Language Institute, Bangkok University.
STUDENTS’ VOCABULARY BREADTH AND THEIR READING PROFICIENCY
1099
The author used to train the reading strategies to her students twice and the author was wondering why the
training did not work. Majority of her students could not apply those strategies when reading, but later on the
author could figure out. Among EFL (English as a Foreign Language) teachers in the Language Institute, they
do agree that vocabulary is the key factor to the language development of their students. However, they have
never done the research on measuring their students’ vocabulary knowledge. The author, therefore, would like
to re-examine the students’ vocabulary breadth in order to obtain empirical proof of this issue.
This present research replicates her previous work (Pringprom & Obchuae, 2011) that the author had
investigated the relationship between students’ vocabulary size and their reading comprehension, but in this
present work, the subjects are studying EN112 (Fundamental English II), which the author assumes that their
vocabulary size should be bigger since the course is one level advanced from EN111 (Fundamental English I)
they completed last semester.
Background to the Study
The Role of English Language in Thailand
English is one of the compulsory subjects in Thailand. It is categorized under the foreign curriculum.
Nowadays, English has been taught since primary grades in Thai public schools or since the kindergarten in the
private schools. In addition, English is a compulsory language to enter public universities in Thailand. It is also
a required course for undergraduate students in every university for both Thai and International programs.
Students are required to complete at least three to four English courses depending on the programs and their
major before graduation. In many work places, English is considered an L2 (Second Language) in both spoken
and written form.
Measuring Vocabulary Breadth
VLT (Vocabulary Levels Test) has become an important tool to measure EFL learners’ vocabulary
knowledge. It is widely used in the research area of SLA (Second Language Acquisition). The test has five
parts corresponding to five levels of word frequencies in English: 2,000, 3,000, 5,000, academic, and 10,000.
The test-item types are used in discrete and context-independent. It tests the target words out of context,
because the context might provide clues to the meanings. The VLT uses a word-definition matching format to
require test-takers to match the words to the definitions. Each level contains 30 items with three definitions on
the right and six words on the left. Test-takers need to choose three out of the six words to match the three
definitions on the right. Read (2007) has mentioned that vocabulary assessment can reveal the extent of the
lexical gap the L2 learners face in coping with their authentic reading materials.
For interpreting the test, Nation (2008) explained that:
Each word in the test represents 33 words (1,000 divided by 30). A score of 20 out of 30 on a level means that a
learner knows 667 words out of the 1,000 at that level, and does not know 333 from that level. We would expect a learner
to know at least 90% of the words at that level (27 out of 30) before we could feel that the level might be known. (p. 143)
Vocabulary Knowledge and Reading Proficiency
It has been recognized that vocabulary knowledge plays an important role in reading comprehension not
only in L1 (first language) but also has proved to be true of reading in L2 settings (Alderson, 2000; Anderson &
Freebody, 1981; Mezynski, 1983; QIAN, 2002; Read, 2000). The study emphasized the role of decoding and
vocabulary skills, as predictors of reading comprehension in young L1 and L2 learners found that vocabulary is
STUDENTS’ VOCABULARY BREADTH AND THEIR READING PROFICIENCY
1100
a critical predictor of the development of reading comprehension skills (Lervåg & Aukrust, 2010). Most
theorists and researchers in education have assumed that vocabulary knowledge and reading comprehension are
closely related, and numerous studies have shown a strong correlation between the two (Baker, Simmons, &
Kameenui, 1995; Laufer, 1992; Nagy, 1988; Nelson-Herber, 1986; QIAN, 1999, 2002; QIAN & Schedl, 2004).
QIAN (1999) found significant correlations in his study with the roles of depth and breadth of vocabulary
knowledge in reading comprehension with 44 Korean and 33 Chinese speakers using version A of the VLT and
the reading comprehension section from the TOEFL (Test of English as a Foreign Language). The correlation
between the two tests was 0.78. QIAN (2002) further investigated the relationship between vocabulary
knowledge and academic reading performance with 217 students attending an intensive ESL (English as a
Second Language) program at the University of Toronto and found that students’ vocabulary knowledge was
positively correlated to the performance of their reading tasks. He, therefore, concluded that vocabulary is a
critical component in reading assessment.
Pringprom and Obchuae (2011) investigated the relationship between students’ English vocabulary size
and their reading comprehension with 30 undergraduate students who studying EN111 at Bangkok University.
The 2,000, 3,000, and 5,000 VLT bilingual version (English-Thai) was used to measure the subjects’
vocabulary size and the RCT (Reading Comprehension Test) was used to assess students’ reading
comprehension. The findings showed positive correlation between the RCT and the VLT 2,000, 3,000, and
5,000 at 0.684, 0.779, and 0.571 respectively.
Laufer (1989) studied the percentage of running words needed to be understood in order to ensure
reasonable reading comprehension of a text. The reasonable reading comprehension score was set at 55% or
more. She found that the group that scored 95% and above on the vocabulary measure had a significantly
higher number of successful readers than those scoring below 95%. In her further study (1992) on the
relationship between reading comprehension and the vocabulary size of L2 learners, which was measured by
two different vocabulary tests, the VLT and the Eurocentres Vocabulary Test. The correlations were 0.50,
significant at the level of p < 0.0001, and 0.75, significant at the level of p < 0.0001 respectively.
Hirsh and Nation (1992) studied the amount of vocabulary demands of three short unsimplified novels
which were written mainly for young native speakers of English, and found that a vocabulary size of 2,000
word-frequencies was not enough for pleasurable reading. They stated that a number of words between 3,000 to
5,000 word families were needed to provide a basis on comprehension (Nation & Waring, 2009). Nation and
Waring (2009) also suggested that an ESL learner needs to know at least 3,000 frequency words of the English
language. Furthermore, HU and Nation (2000) compared the effect of four text coverages on reading
comprehension of fiction text and found that learners needed to know around 98% of the running words in the
text to gain adequate comprehension.
Beglar and Hunt (1999) conducted an identical study with 496 Japanese high school students using four
versions of the VLT 2,000 and 464 students using four versions of the University Word List (UWL) from the
same test. They found that scores on the reading comprehension test were correlated with scores on versions A
and B of the VLT 2,000 at 0.66 and 0.62 and with scores on versions A and B of the UWL at 0.67 and 0.71.
ZHANG and Anual (2008) studied the role of vocabulary in reading comprehension with 37 secondary
students learning English in Singapore using the VLT to measure students’ vocabulary knowledge and found
that students’ vocabulary knowledge at the 2,000-word and the 3,000-word levels were correlated to their
reading comprehension.
STUDENTS’ VOCABULARY BREADTH AND THEIR READING PROFICIENCY
1101
Brown (2010) investigated a reciprocal relationship between vocabulary knowledge and comprehension in
L2 text with 50 first-year students at the University of Botswana and found that the relationship between the
two was reciprocal.
All studies reviewed above confirm the close relationship between vocabulary knowledge and English
reading proficiency.
Research Objectives
There are two objectives to this research: (1) to examine students’ vocabulary breadth and (2) to explore
the relationship between students’ English reading proficiency and their vocabulary size. Followings are the
author’s research questions: (1) What is the overall vocabulary breadth of the students? (2) Is there a significant
relationship between students’ scores on the RCT and the scores on the VLTs?
Methodology
Subjects
Two sections of English classes consisting of 81 students were purposively selected as the subjects for this
study. They were first-year-undergraduate students studying EN112 in the second semester of academic year
2010 at Bangkok University.
Instruments
The 2,000, 3,000, and 5,000 VLT bilingual version (English-Thai) was used to measure the subjects’
vocabulary breadth in this study. The bilingual version is based on the original version B of N. Schmitt, D.
Schmitt, and Clapham (2001). Each level contains 30 items with three translations on the right and six tested
words on the left. Subjects were supposed to choose three out of six words to match the Thai-translations on the
right.
As for scoring, each correct translation was awarded one point; a total score for each level was 30 points
(see Figure 1).
1 business
1 business
2 clock
__ _ กําแพง
3 horse
_ __ มา
4 pencil
__ _ ดินสอ
You answer it in this way.
2 clock
_ 6_ กําแพง
3 horse
_ 3_ มา
4 pencil
_ 4_ ดินสอ
5 shoe
5 shoe
6 wall
6 wall
Figure 1. A Sample of test items.
A multiple-choice-question-format RCT was used to assess the subjects’ reading proficiency. The test consists
of eight short passages, carefully selected from a pool of short reading texts that were suitable to the subjects’
English level by Language Institute teachers. There are 30 questions with only one correct answer and three
distracters for each question; the subjects were supposed to select the best choice among a set of four options.
As for scoring, a correct answer to each question was given one point. The total score for the RCT is
30 points. The test was reviewed and validated for its content, appropriateness, and practicality by three
EFL teachers.
STUDENTS’ VOCABULARY BREADTH AND THEIR READING PROFICIENCY
1102
Procedure
Before conducting the research, trial version of the original VLT and the RCT were administered with 43
students who had similar profiles in order to check the appropriateness of the both tests. It was found that only
a few words were required to be adjusted and revised for the RCT. During proctoring, the author observed that
students had difficulty with the VLT. The author had them verbally respond on the original VLT. Many of them
told the author that they knew the words on the left, but they could not translate the statement items on the right.
The word introduce was taken for an example, they could not match it correctly, because they did not
understand the three English definitions, although they knew what introduce meant since they used this word a
lot when they gave the project presentation in the class. Therefore, the author decided to develop a bilingual
version. Thai Software Dictionary version 7.0 of So Sethaputra was used as lexical references for Thai
translation. After revision, the VLT bilingual version was validated by three EFL teachers using the back
translation process. The bilingual version is more valid measures for lower proficiency learners, because it is
easier for them to understand an L1 translation (Nation, 2008). Two weeks later, the bilingual version of VLT
and RCT were retested by the same group of students.
To avoid testing exhaustion, which may affect subjects’ proficiency, the data collection was carried out at
different times. In the first week of the course, the VLT 2,000, 3,000, and 5,000 was administered at the
beginning of class time. Instructions and procedures were clearly explained in Thai, because the subjects
seemed to be unfamiliar with the VLT format. How to answer the VLT was also demonstrated on the white
board. While taking the test, the subjects were allowed to ask questions relating to the test administration, not
the test’s content. The subjects were told to leave the answer blank if they did not know the meaning of the
word in order to prevent any chance of guessing correctly, which in turn might affect the true scores the
subjects should really gain. The average time the subjects spent on the VLT was approximately 30 minutes.
In the second week of the course, the RCT was administered at the beginning of class time. Instructions
were explained and the subjects were given one hour to complete the reading test. The subjects were assured
that scores from both tests would not affect their grade. This was mentioned to let them know that they did not
have to randomly guess the answer. However, they were told to try their best to examine how their English
knowledge was. Both tests were taken in a quiet classroom under favorable examination conditions.
Results
Table 1 demonstrates the means and standard deviations for the VLT 2,000, 3,000, and 5,000 frequency
levels. As can be seen, the mean scores for the three frequency levels are considerably low. Since each word in
the test represents 33 words (Nation, 2008), this can be interpreted that the subjects knew 579 words out of
1,000 at the 2,000 level; 521 words out of 1,000 at the 3,000 level; and 287 words out of 1,000 at the 5,000
level respectively.
Table 1
Obtained Scores on the VLT Frequency-Words Levels (N = 81)
Levels
Number of items
Mean ( x )
SD (Standard deviation)
2,000
30
3,000
30
5,000
30
17.54
15.79
8.70
5.43
5.18
3.62
STUDENTS’ VOCABULARY BREADTH AND THEIR READING PROFICIENCY
1103
Figure 2 below shows the overall subjects’ average scores of the VLT by percentage. It is obvious that the
subjects’ vocabulary knowledge is lower than the possible threshold for comprehension, especially, the scores
of 2,000-level (58.46%) and 3,000-level (52.63%) which are high frequency word-levels. The subjects’ VLT
score undoubtedly dropped at the 5,000 word-level (29%).
Figure 2. Subjects’ scores of the VLT by percentage (N = 81).
Pearson correlations were conducted between scores on the RCT ( x = 16.53; SD = 5.12) and the scores
on the VLT frequency-words levels. As can be seen in Table 2, show strong correlations between the RCT and
the VLT 2,000 at 0.754 (p ≤ 0.001), the RCT and the VLT 3,000 at 0.776 (p ≤ 0.001), and the RCT and the
VLT 5,000 at 0.633 (p ≤ 0.001).
Table 2
Pearson Correlations Between Scores of the RCT and the VLT Frequency-Words Levels (N = 81)
VLT 2,000
0.754**
(0.000)
RCT
VLT 3,000
0.776**
(0.000)
VLT 5,000
0.633**
(0.000)
Note. ** Correlation is significant at the 0.01 level (2-tailed).
Discussion
Research question one asks that what the overall vocabulary breadth of the students was. The results show
that small amount of words within the level of 2,000 and 3,000 are known and very few words on the level of
5,000 are recognized by the subjects. The subjects’ scores drop sharply on the VLT 5,000, because words tested
in this level are low frequency-words; they are more difficult compare to the tested words in the 2,000-3,000
frequency-words levels.
It can be inferred according to the findings that vocabulary breadth of the students is far from the threshold
of vocabulary breadth for comprehending the written text. With reference to Hirsh and Nation (1992) a
vocabulary size of 2,000 to 3,000 words provides a good basis for language use. For Laufer (1992), 3,000
words family level is a minimum for the reading of unsimplified text. With an inadequate amount of vocabulary,
students have obtained will impede their comprehension on any kinds of English written text. Researchers
(Nation, 2008; Read, 2000; Laufer, 1992) believe that even knowing 89% of the words in a text does not
guarantee the correct guessing of the meaning of the unfamiliar words in a passage; at least 98% of running
words in the text is needed to gain adequate comprehension (Nation, 2006).
Comparing with the author’s previous research (Pringprom & Obchuae, 2011), which the mean scores of
the subjects (n = 30) on the VLT 2,000 was 15.53 (51.78%), the VLT 3,000 was 14.37 (47.89%), and the VLT
STUDENTS’ VOCABULARY BREADTH AND THEIR READING PROFICIENCY
1104
5,000 was 9.27 (30.89%), the results of this present study are almost the same although these subjects had
passed EN111 last semester; their vocabulary knowledge did not seem to progress very much. The findings are
very useful; we as teachers have to think in what way we could do more to help our students develop their
vocabulary through each level.
It can be concluded that passing EN111 was not conclusive to increasing students’ vocabulary size.
Moreover, studying English subject for many years in school does not help in preparing students for English
courses at the university level. To be successful English learners, the students may have to practice English
outside the traditional classroom setting by reading English texts, listening to English news, and watching films
with an English sound track, all of which require a lot of language learning motivation.
Unlike English language’s role in other Asian countries, for example Singapore, China, and Hong Kong,
English is not really an L2 in Thai context. Furthermore, excellent English communication is required only for
a few professions in Thailand, which might result in our students’ language learning motivation. Students
probably do not consider that by not knowing English, it would hold them back from getting a job.
In conclusion, the overall vocabulary breadth of the subjects is inadequate for successful language use or
for providing basic text comprehension, especially when it is compared to their academic level.
Research question two asking whether there is a significant relationship between students’ scores on the RCT
and the scores on the VLTs. Results indicate a strong level of correlations between the RCT and the VLT 2,000,
VLT 3,000, and VLT 5,000 at 0.754, 0.776, and 0.633 respectively. As can be seen, the RCT most correlates with
the VLT 3,000 (r = 0.776), which is corresponded to the author’s previous work (Pringprom & Obchuae, 2011).
According to the results, it can be inferred that English reading proficiency as measured by the RCT and
vocabulary breadth as measured by the VLT 2,000, 3,000, and 5,000 frequency-words levels are related: The
higher subjects score on the RCT, the higher they score on the VLT or vice versa. However, by looking at the
correlation size of the RCT and the VLT 5,000, there may be a question why the 5,000 frequency-words level
shows least correlation (r = 0.633). It could be explained that the coverage of reading texts in the RCT mainly
contains 2,000-3,000 high frequency-words. The results from this study support early claims that vocabulary has
played an important role in L2 reading proficiency (Anderson & Freebody, 1981; Beglar & Hunt, 1999; Hirsh &
Nation, 1992; Mezynski, 1983; Pringprom & Obchuae, 2011; QIAN, 2002; Read, 2000; ZHANG & Anual, 2008).
Conclusions
Numerous studies reveal that vocabulary knowledge is closely related to the reading proficiency among L2
learners. Learners will have a difficult time to comprehend the reading text, even to make an appropriate
guessing, if their vocabulary size is far from the required threshold. The findings are giving the alarm of
vocabulary knowledge deficiency of our students. For pedagogical implication, the author would suggest that in
order to increase our students’ vocabulary knowledge, critical vocabulary training should be implemented in
regular English courses immediately. Assessment emphasizing the students’ vocabulary size should also be
done regularly in order to monitor their vocabulary development.
Limitation
This study was carried out with only 81 undergraduate students; the data obtained did not allow the author
generalize the results for all Bangkok University students. Further research on assessing students’ vocabulary
knowledge with a larger and more varied of subjects is needed.
STUDENTS’ VOCABULARY BREADTH AND THEIR READING PROFICIENCY
1105
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