It is true that vocabulary is central to a language and is of paramount importance to a language learner as Ellis (1994) claims that "the cornerstone of L2 is its vocabulary. Instruction is an important contributor in the development of vocabulary knowledge. Implicit vocabulary teaching and learning method involves indirect, or incidental whereas the explicit method involves direct, or intentional. This thesis attempts to find out and compare the effects of the two vocabulary teaching methods on 60 students studying in a Tonekabon University. Control Group (explicit vocabulary teaching) and Experimental group (implicit vocabulary teaching), each group was given a different modes of instruction. During the lessons different explicit vocabulary presentation techniques used including mind-mapping, Persian equivalents and English synonyms and definitions. Subsequently, the teacher utilized an inferred method for teaching vocabulary implicitly which means students were supposed to guess the words from the passages by using context clues. The researcher used the, the Independent T-Test, Analysis of covariance. The T-tests compared the means of the pretest and posttest scores of each group. ANCOVA was used to identify the progress level from the pretest to the posttest in the groups. The results obtained by the implicit group shows students gained new vocabulary moderately better. And also findings of study in the explicit vocabulary teaching method revealed that in terms of students' short term recall of word meanings and the students did well in word retention. The results of this study have important implications for the classroom and make a strong case for implicit and explicit vocabulary instruction.
Word knowledge, Vocabulary Learning Strategy, Implicit Vocabulary Instruction, Explicit Vocabulary Instruction
1. Background of the Study
Vocabulary teaching is one of the most important components of any language classes which help learners to understand languages and express their meanings. If language structures make up the skeleton of language, then it is vocabulary that provides the vital organs and the flesh (Harmer 1993.153). This study provides the view toward students' knowledge of words by the influence of different modes of teaching vocabulary in which students are weak in words retention. My interest in vocabulary learning strategies was first aroused when I was an English teacher in Institutes. Year after year, many students complained about the difficulty of memorizing new words. They had realized that their small vocabulary size, which seemed difficult to enlarge, had hampered their English learning. It seemed that they had not found an appropriate way to learn vocabulary.
We have not been taught the majority of words which we know. Beyond a certain level of proficiency in learning a language, vocabulary development is more likely be mainly intentional or incidental. In vocabulary acquisition studies, one key research direction is to explore the points at which implicit vocabulary learning is more efficient than explicit vocabulary learning, to ask what are the most effective strategies of implicit learning, and to consider the implications of research results for classroom vocabulary teaching(Carter and Nunan, 2002).Traditional vocabulary instruction for many teachers involves having students look words up in a dictionary, memorize them in word lists, find the nearest equivalent which are often used in order to help students learn new words. But these methods provide what research and theory tell us about word learning and sound vocabulary instruction.
2. Statement of the Problem
All instructors through classroom activities usually use different methods and techniques in order to teach vocabulary in the class in which students participate actively. Moreover, the way of teaching is significant in vocabulary learning classes. Among researchers, vocabulary has been concerned the core of learning a language and reading comprehension. Students usually are assumed to learn or memorize the lists of vocabulary in order to increase the knowledge of vocabulary and apply it in understanding passages. Most students suffer from understanding the passages which consist of words that play as a hinder in their perceiving, so teachers should help students out by some principal instruction to make them easy to recognize the meaning of unknown words. Students who are learning English as a foreign language lack the vocabulary necessary to understand the reading material in literature and in the content areas. Many of these students do not have success in reading and listening due to a deficiency in vocabulary. Unknown words hinder students' understanding not only on the reading comprehension portions of these tests, but on understanding of questions on content portions of tests as well. Therefore, it is necessary that successful strategies be found to help these students attain proficiency in the classroom. It has long been a debate as to whether or not explicit instruction increases the acquisition of a second language (Chaudron, 1988). Improvements in reading comprehension in English language learners after explicit vocabulary instruction would provide useful strategies for not only EFL instructors, but for mainstream teachers of classrooms with EFL students. The problem for this study is to investigate the merits. Thus, the purpose of this study is to explore the effect of explicit and implicit instruction on a development of EFL learners' vocabulary learning.
3. Literature review
According to Celce-Murcia (2001) knowledge can be gained and represented either implicitly or explicitly and both contribute to language learning. There exists a central debate emerging from the studies dealt with whether effective vocabulary learning should give attention to explicit implicit vocabulary learning.
In implicit vocabulary, learning students engage in activities that focus attention on vocabulary. Incidental vocabulary is learning that occurs when the mind is focused elsewhere, i.e. learning without conscious attention or awareness; such as on understanding a text or using language for communicative purposes. From a pedagogically- oriented perspective, the goal of explicit teaching is "to lead learner's attention", whereas the aim of an implicit focus on form is "to draw learner's attention". Moreover, individual tasks can be located along an explicit or implicit continuum, and complex tasks may combine both explicit and implicit subtasks. Most researchers recognized that a well-structured vocabulary program needs a balanced approach that includes explicit teaching together with activities providing appropriate contexts for incidental learning.
Much discussion in the literature on whether vocabulary is best learned through direct study or incidentally through reading. Schmitt (2000) suggests that learners are able to learn large quantities of vocabulary explicitly, for example, by using word lists and the 'depth of processing' hypothesis suggests that it is more likely for a piece of information to be retained in memory if it is manipulated with more mental effort. On the other hand, Hulstijn (1997) notes that it is difficult to learn everything we need to know, through explicit learning, about the more frequent words but extensive reading can serve this purpose. There is, in fact, evidence that both the explicit and implicit approach can be effective. In light of the drawbacks and benefits of both the explicit and implicit vocabulary learning methods, some linguists have suggested that both methods be used together to supplement each other.
The experimental design for this study was a quantitative design. Specifically, the design was a quasi-experimental. This research used two groups, control group and experimental group with no treatment (explicit instruction) and a treatment (implicit instruction). The two methods of instruction were compared. Pretest-posttest experimental design was used to investigate the effectiveness of using implicit and explicit modes of introduction to enhance vocabulary knowledge.
In scoring the items on the test, for the vocabulary-recognition portion, the items were multiple choices. Scoring was objective; one point for each correct answer. Scores ranged from 0 to 20 on this portion. On the second section of the test, the vocabulary production portion, the items were fill-in-blank. In order to earn the maximum score of one point for each item, the response had to be grammatically correct and spelled correctly. Scores ranged from 0 to 20 on the production portion of the test. For the vocabulary acquisition portion of the test, the total measures ranged from 0 to 20.
For the vocabulary acquisition measures, participants took pre-tests to identify whether or not they had any existing knowledge about the vocabulary that was the focus for the particular unit. For this study, it was important to be able to identify the number of vocabulary words that were gained (pre- versus post- scores) as opposed to identifying only the number of vocabulary words that were known at the end of the unit (post-test only). By administering pre-and post-tests, the researcher was able to remove any influence of prior knowledge of these vocabulary words by the participants. By obtaining several values for each participant and alternating the methods of instruction, the researcher was able to help overcome the small sample size and the possibility of maturation of the participants. This also helped to decrease the effect for a particularly interesting unit or particularly uninteresting unit. The final analysis of the data was approximately three months. Table 2 illustrates the timeline of the experiment with reference to the pre-tests and the units of instruction.
To collect data for this study, three instruments were utilized :( 1) OPT test t; (2) pretest (i.e. a TOEFL Vocabulary test; (3) posttest (i.e. A TOEFL proficiency test) Vocabulary Levels Tests (Nation, 1990), which is among the best known vocabulary measurement tools to date, will be selected to determine the size of the participants' vocabulary.
A comparison of the mean scores of test obtained by the two groups shows that, very obviously, performance was a bit higher when the target words were taught through an implicit vocabulary instruction technique of inferred passage than when target words were associated with mid-mapping technique and synonyms and definitions in the passages. The students who participated in this study were sixty students enrolled in university in one semester. The test scores for all sixty students were collected and listed with a numerical reference rather than by name. (Refer to Appendix B) In this study, participants took part in six vocabulary units. These units were a part of 400 must-have words for the TOEFL about the same length, and on various topics. Within this program, there were also teacher-reviewed vocabulary lists and classroom tested strategies for implicit and explicit vocabulary teaching. Each part was on the same vocabulary level and the units were designed to be of similar length. There were two different modes of instruction. In one mode of instruction, implicit instruction, the teacher utilized a inferred method for teaching a vocabulary unit. Moreover, students were supposed to guess the words from the passages by using context clues. In the other mode of instruction, explicit instruction, the teacher utilized specific strategies for (mind-mapping technique, synonyms and definitions). Table 2 outlines the daily schedule for each unit. It distinguishes the implicit instruction strategies from the explicit instruction strategies. The independent variable for this study was the mode of instruction implicit classroom instruction versus explicit vocabulary instruction. These modes were applied to the same group of students, but alternated on the basis of the vocabulary unit. The dependent variables for this study were the vocabulary gained and scores-both of which were collected on the basis of each vocabulary unit (approximately every week).
For the vocabulary scores, the lowest possible score was 0 and the highest possible score was 20. Since the focus of this study was to compare conditions with and without explicit vocabulary instruction, the number of words gained for each unit was used.
1-Does explicit teaching of vocabulary affect Iranian EFL learners' knowledge of vocabulary?
2-Does implicit teaching of vocabulary affect Iranian EFL learners' knowledge of vocabulary?
3-Does the experimental groups (implicit) of the study show progress from the pre-test to post-test?
4-Does the control group (explicit) of the study show progress from pre-test to the post-test study?
The hypotheses used for this analysis are as follows:
4. Research Hypotheses
H1: Explicit teaching of vocabulary does not affect Iranian EFL learners' knowledge of vocabulary.
H2: Implicit teaching of vocabulary affects Iranian EFL learners' knowledge of vocabulary.
H3: The experimental(implicit) of the study shows progress from the pre-test to post-test of study.
H4: The control group (explicit) of study does not show progress from pre-test to the post-test study.
The research participants for the study included the researcher as the classroom teacher and two groups of students. The total of 60 undergraduate students were (40 males and 20 females) of English as a Foreign Language in the Islamic Azad University of Tonekabon, Iran. Their age ranges from 19 and 23. Informed consent was obtained from all students verbally. These students were chosen in the diversity of the group including characteristics such as gender, age, and years of learning English as a Foreign Language.
Some 30 students majoring in English were chosen. As previously discussed in the rationale for this research, this kind of situation often places high stress on students as well as teachers and leads to a classroom instructional focus geared toward rote memorization (explicit) rather than higher level thinking (implicit). It was within this context that this researcher sought answers to the questions guiding this study.
Two sets of test scores of a single group of sixty students were analyzed to determine if a statistically significant gain existed. The independent t-test was used to determine if the mean gains of the two groups of scores were significantly different from one another. The t-test was chosen because it adjusts for the distribution of the small sample size.(Gay & Airasian, 2003). The test was run first for the vocabulary acquisition variable (refer to Hypothesis 1) and then again for the vocabulary knowledge variable (refer to Hypothesis 2). Statistically significant gains in the means of the groups of scores (control group) would indicate that explicit vocabulary instruction does have an effect in EFL words retention. A positive difference would be an indication of additional benefits (more vocabulary acquired and/or higher retention) derived from the implicit instruction. In examining the overall classroom performance, a higher average on units taught using explicit vocabulary instruction would indicate an overall benefit for using explicit vocabulary instruction in the classroom.
The OPT test and pretest were administered one week apart, with the second test administered the day prior to implementation of the program. The posttest was administered immediately upon the conclusion of the study. All data were collected during the students' regularly scheduled vocabulary class by the researcher who had no relationship with classroom participants .It could be one of the limitations of the study. Students in both study conditions received the same pretest and posttest. Test directions instruct students in order to receive full credit; all work must be shown, regardless of how they arrive at their answer. Students were allowed and required to utilize some techniques to answer questions on the test.
For this research study, the modes of instruction were the independent variable because it was hypothesized to impact the vocabulary knowledge on the posttest. The dependent variable was the vocabulary knowledge measured by the posttest scores after the treatment. The analysis would use two methods to data analysis in order to answer the research questions: the independent T-Test and ANCOVA. Independent T-tests were used to answer the first and second research question. ANCOVA was used to answer the third and fourth research questions.
This research study aimed to investigate the effects of vocabulary modes of instruction on word knowledge for an experimental group (N=30) of college students at the Islamic Azad University, Tonekabon, Iran. In order to compare the improvement from the pretest to the posttest of the study, the researcher used the, the Independent T-Test, Analysis of covariance (ANCOVA). The T-tests compared the means of the pretest and posttest scores of each group and, therefore to answer the first research question and second question. ANCOVA was used to identify the progress level from the pretest to the posttest in the groups, and therefore to answer the third and fourth research questions. In this section the results of the study based on the participants' scores on the pretests and posttests in both groups will be presented.
H1: Explicit teaching of vocabulary does not affect Iranian EFL learners' knowledge of vocabulary. As viewed in Figure 4.1, the histogram forms a symmetric shape confirming that the scores are normal. For answering question one, two sets of test scores of two group students were analyzed to determine if a statistically significant gain existed. The independent t-test was used to determine if the mean gains of the two groups of scores were significantly different from one another. According to (Table 4.2), observed t value equals 2.343. A comparison made between this t value and the critical t value in the table (Table 4.4) adopted from Hatch and Farhady (1981, p. 272) shows that the critical t value equals 2.In other words the observed t is higher than the critical t value. Therefore, the null hypothesis derived from the first research question is rejected and it can be indicated that the research independent variable explicit teaching of vocabulary has effect learners' knowledge of vocabulary.
Table 4.2 Independent Samples Test
Levene's Test for Equality of Variances
t-test for Equality of Means
Std. Error Difference
95% Confidence Interval of the Difference
Equal variances assumed
Equal variances not assumed
Table 4.1 implicit and explicit posttest score
Table 4.3 pretest and posttest of experimental group
As Table 4.3 displays, the results of the descriptive analysis showed how the participants performed on the pretest and the posttest as well as the dispersion of the scores on the two tests. The mean scores of the pretest and the posttest in the Experimental Group were M = 11.26 (N = 30, SD =1.375) and M = 14.74 (N = 30, SD = 2.782) respectively. The significant difference between the two mean scores and the standard deviation indicated the group performed heterogeneously before and after the treatment. Having calculated the descriptive statistics based on the students' scores on the pretest and the posttest, the researcher conducted a T-test to determine if the means significantly different.
Table 4.4 Descriptive Statistics of the Overall Comparison between Pretest and Posttest in the CG
Table 4.4 shows comparisons between the pretest and the posttest mean scores for the experimental group. The purpose of this comparison is to find out whether the participants in the EG made changes in their vocabulary knowledge performance after the treatment. There is a statistically significant difference between the pretest and posttest performance of the groups (p>.05). There was no statistical evidence found to reject the second null hypothesis.
H2: Implicit teaching of vocabulary affects Iranian EFL learners' knowledge of vocabulary. Tables 4.4 shows comparisons between the pretest and the posttest mean scores for the control groups. The purpose of this comparison is to find out whether the participants in CG made changes in vocabulary knowledge after treatment. There is not a statistically significant difference between the pretest and posttest performance of the group (p>.05). This means the EG did significantly improve their vocabulary knowledge after the treatment.
We can come to a conclusion that both the explicit vocabulary teaching technique (mind-mapping) and the implicit vocabulary teaching approach (inferred passage) brought lexical gains to the students in both groups. This finding is in line with the viewpoint of Carter and Nation (2001), who suggest that both the explicit and implicit methods can be effective.
Nevertheless, in comparison, when word meanings were explicitly taught to the subjects through mind-mapping, semantic and short term recall of the target words were better than when the word meanings had to be inferred from the passages. This finding ran to Krashren's argument that 'competence in and vocabulary is most efficiently attained by comprehensible input in the form of reading' (Krashen 1989, p.440). Krashen maintains that according to his Comprehensible Input Hypothesis which assumes that we acquire language by understanding messages (p.440), comprehensible input is the essential to language acquisition and 'vocabulary and spelling are acquired in the same way the rest of language is acquired' (p.440).
H3: The experimental(implicit) of the study shows progress from the pre-test to post-test of study. Before answering this question and presenting the descriptive results based on the experimental group's scores on the pretest and posttest of the study, the issue of whether or not scores follow a normal distribution should be investigated. Figure 4.5 is the histogram of the scores with a symmetrical shape showing the normality of the distribution.
On the basis of the table (4.7), that the F value in the treatment row equal is 18.635 above shows that there is a significant different between the two research groups (EG, CG). In addition the sig. value (.000) in the same row shows that it is above the p-value (p>0.5). Hence it is stated that different between the mean scores is not haphazard or accidental and the third hypothesis supported and fourth null hypothesis is rejected.
In order to answer this question, ANCOVA was conducted for finding any significant differences in the level of progress achieved by the control group. In all of these analyses the significant level was set at p < .05.
H4: The control group (explicit) of study does not show progress from pre-test to the post-test study. In order to answer this question, ANCOVA was conducted for finding any significant differences in the level of progress achieved by the control group. In all of these analyses the significant level was set at p < .05.
It is true that vocabulary is central to a language and is of paramount importance to a language learner as Ellis (1999) claims that "the cornerstone of L2 is its vocabulary. Instruction is an important contributor in the development of vocabulary knowledge. Implicit vocabulary teaching and learning method involves indirect, or incidental whereas the explicit method involves direct, or intentional. This paper attempts to find out and compare the effects of the two vocabulary teaching methods on 60 students studying in a Tonekabon University. Control Group (explicit vocabulary teaching) and Experimental group (implicit vocabulary teaching), each group was given a different modes of instruction. During the lessons different explicit vocabulary presentation techniques used including mind-mapping, Persian equivalents and English synonyms and definitions. Subsequently, the teacher utilized an inferred method for teaching vocabulary implicitly which means students were supposed to guess the words from the passages by using context clues. The researcher used the, the Independent T-Test, Analysis of covariance. The T-tests compared the means of the pretest and posttest scores of each group. ANCOVA was used to identify the progress level from the pretest to the posttest in the groups. The results obtained by the implicit group shows students gained new vocabulary moderately better. And also findings of study in the explicit vocabulary teaching method revealed that in terms of students' short term recall of word meanings and the students did well in word retention. The results of this study have important implications for the classroom and make a strong case for implicit and explicit vocabulary instruction.