JOLLT Journal of Languages and Language Teaching https://e-journal.undikma.ac.id/index.php/jollt Email: jollt@ikipmataram.ac.id & jollt@undikma.ac.id DOI: https://doi.org/10.33394/jollt.v%vi%i.4995 April 2022. Vol. 10, No, 2 p-ISSN: 2338-0810 e-ISSN: 2621-1378 pp.211-222 JOLLT Journal of Languages and Language Teaching, April 2022. Vol.10, No.2 | 211 THE EFFECTS OF VOCABULARY MASTERY ON ENGLISH- SPEAKING ABILITY: A META-ANALYSIS STUDY 1Helli Kristiana Br Bangun, 2Debora Chaterin Simanjuntak 1Fakultas Keguruan dan Ilmu Pendidikan Universitas Advent Indonesia Corresponding author email: bangunhelli@gmail.com Article Info Abstract Article History Received: February 2022 Revised: March 2022 Published: April 2022 The purpose of this meta-analysis is to analyse the effects of vocabulary mastery on English-speaking ability, which has been a extensively focused on English language teaching. A descriptive qualitative technique was utilized in this study. The data of this study consisted of 820 samples from 21 studies that focused on the correlation between students' sufficient academic vocabulary and English- speaking ability. The meta-analysis involves the studies conducted in Indonesia to draw deeper characteristics of the phenomena. The r and n were found in the data. n is the number of respondents, and r is the coefficient value. The researchers utilized five procedures to acquire the data: collecting studies or meta-analysis materials; calculating the effect size of each study; estimating the summary effect or mean effect size; analyzing the standard error; and evaluating publication bias. The data was analyzed with the help of JASP program. Because K = 21, 5K+10 Equals 115. The obtained fail-safe N value is 4727.000, with a significant target of 0.05 and p < 0.001. Because N > 5K+10 is a safe value, it is assumed that no publication bias exists in the Meta-Analysis study. In addition, the study's findings demonstrate that having an adequate academic vocabulary has a positive impact on English-speaking skills. Keywords Vocabulary Mastery; Speaking Skills; Meta-Analysis How to cite: Bangun, H. K. B., & Simanjuntak, D. C. (2022). The Effects of Vocabulary Mastery on English- Speaking Ability: A Meta-Analysis Study. JOLLT Journal of Languages and Language Teaching, 10(2), pp. 211-222. DOI: https://doi.org/10.33394/jollt.v%vi%i.4995 INTRODUCTION Focusing on Indonesia, English has been the most in-demand subject at schools (Syafrizal et al., 2021). Viewed from parents’ perspectives, English language is to be learned from an early age. Realizing the importance of the language, most parents require their children to learn English from kindergarten to university because they believe that learning at the early age will help their children establish good thinking stimulation in absorbing knowledge (Bissonnette & Boyer, 2022). There is ample research done in various countries investigating the importance of vocabulary mastery on speaking ability development. It is undeniable that the majority of EFL learners struggle in enhancing their speaking skills because when it comes to speaking, they have to consider various abilities, namely fluency, complexity, pronunciation, enunciation, voice quality development, and so forth (Fatimah, T., Purwanti, S. E., & Mustajib, 2019). However, a variety of factors hinder EFL learners’ capacity to communicate in English. In speaking, students tend to use recognized or high-frequency words in daily speech. They end up having insufficient academic vocabulary. When they come across novel terms, they are likewise inexperienced with how to comprehend and use them in classroom settings. Vocabulary mastery, according to Putri and Refnaldi (2020), could be one of the factors influencing students' English-speaking ability. The students' limited vocabularies may make it difficult for them to speak English in a more natural way. As a result, it's possible that this is causing the slow improvement in speaking. Vocabulary knowledge has been seen as an initial skill that must be mastered by EFL learners to improve other language skills. Fundamentally, https://e-journal.undikma.ac.id/index.php/jollt mailto:jollt@ikipmataram.ac.id http://issn.pdii.lipi.go.id/issn.cgi?daftar&1366476729&1&& http://issn.pdii.lipi.go.id/issn.cgi?daftar&1524725326&1&& mailto:bangunhelli@gmail.com Bangun and Simanjuntak The Effect of Vocabulary Mastery ……….. JOLLT Journal of Languages and Language Teaching, April 2022. Vol.10, No.2 | 212 vocabulary knowledge is a prerequisite for most other language skills (Dakhi & Fitria, 2019). Several studies on vocabulary and speech have been undertaken in the past. Uzer (2017) conducted one of the most widely cited studies, in which he investigated the relationship between vocabulary mastery and improved speaking skills in EFL students in senior high school. The statistical connection between them was 0.630, indicating that studying vocabulary plays a major influence in improving students' speaking skills. (Taslim, T., Asrifan, A., Chen, Y., & Nurdania, 2019)investigated the relationship between students' vocabulary knowledge and speaking ability in eleventh graders. To link the two variables, they used a correlative design. The participants in this study were all science students in the eleventh grade (XI2), with a total of thirty-two students in the subject. To test their hypothesis, the researchers analyzed the data using the SPSS 21 program using Pearson Product Moment Correlation and Linear Regression. As a result of the computations, the r value of 0.532 was determined. It has been demonstrated that a student's vocabulary mastery and speaking abilities have a considerable significant correlation. There have been numerous analytical discussions and comprehensive studies on the importance of improving vocabulary knowledge; however, this study is unique in that it explains the magnitude of the effect of vocabulary mastery in acquiring sufficient academic words, as well as what factors should be controlled for to help increase the effect size. In mild of the foregoing discussion and to add to the literature, toward the existing day the researchers wanted to delve into correlation between students' vocabulary mastery and English-speaking ability in meta-analysis study. Meta-analysis is considered to be a statistical tool for estimating the advocate and variance of underlying populace penalties from a collection of empirical research (Field AP, 2010). Henceforth, general impact of vocabulary mastery on English- speaking ability is discovered in this study. This study provides an opportunity to obtain an overview of vocabulary mastery that has been intensively discussed in the world of English language teaching. In addition, the following research questions will be addressed by this project: 1. What is the effect size of vocabulary mastery on English-speaking ability? 2. Is there publication bias? 3. Is there a positive relationship between vocabulary mastery and English speaking ability? Vocabulary as Main Communication Tool English has been a particular subject at schools and many EFL learners struggle in having sufficient number of vocabulary to develop the four macro skills: listening, speaking, reading and writing (Syafrizal et al., 2021). The value of vocabulary is predominant; wherein, EFL learners must consider that vocabulary is an important part of standards-based curriculum alignment. Unfortunately, most EFL learners hesitantly learn English because they do not have the audacity to speak in classroom situation (Studies et al., 2022). In order to have a successful communication on expressing thoughts and ideas, vocabulary mastery should be established. The larger the vocabulary of the learners, the more effective they speak in the target language. In classroom setting, vocabulary teaching and learning is the most crucial part of a lesson. English-speaking Ability Human communication is important in our lives. People communicate in general to deliver messages, convey and change information, and report on what is going on in their life. This is the fundamental foundation of the EFL setting, in which the ability to speak a global language offers learners with enormous benefits, as it allows them to expand their knowledge and skills in terms of job-related matters. As a result, speaking is known as the main skill for EFL students to possess. It can also be characterized as a process that necessitates the expressing Bangun and Simanjuntak The Effect of Vocabulary Mastery ……….. JOLLT Journal of Languages and Language Teaching, April 2022. Vol.10, No.2 | 213 of thoughts and feelings: which means that thoughts will spring to mind and a person will articulate what he thinks. However, many research claims that students’ speaking skill is significantly low. Insights on tackling speaking difficulties should be obtained from various research (Zainurrahman & Sangaji, 2019). With the advancement of education, there has been a pressing need for new teaching and learning models that are suited to the needs of today's youth. on improving speaking ability (Omar et al., 2020). Speaking is a type of spoken language that is used to express thoughts and feelings. One of the most crucial language skills that students and everyone must master is speaking. Therefore, everyone must be aware of the importance of vocabulary Mastery (Taslim, T., Asrifan, A., Chen, Y., & Nurdania, 2019). According to (Nunan, 2003), Speaking ability is a set of abilities that includes oral language and results in a system for communicating verbal meanings. The ability to express and convey feelings, ideas, or concepts to another person through the use of words or sentences is referred to as speaking ability. (Richards & Willy, 2003) define speaking as an action that defines the active language of language users who demand actual initiatives in the use of language to express themselves vocally. In English classroom settings, speaking plays a crucial part because it is considered as a productive talent that generates language through sound, necessitating the employment of the vocal track and the brain. People frequently rate a person's language proficiency based on their ability to talk rather than their other language skills in many situations. People are becoming more conscious of the importance of communicating in many facets of life, which is causing this issue. People want to say something to accomplish a specific aim, according to (McDonough, 2013). This action includes expressing one's thoughts and beliefs, expressing a desire to achieve something, negotiating or resolving a situation, and establishing and maintaining a relationship. Additionally, students report that mastering the skill of speaking is the most enjoyable. However, it also becomes the most difficult (Darancik, 2018). RESEARCH METHOD Research Design This study utilized descriptive qualitative It was used to see if there was a link between students' vocabulary mastery and their ability to communicate in English. In collecting data, the researchers first collected study material or meta-analysis for the last 6 years, starting in 2017- 2022. second, Calculate the effect size of each study. third, calculate the summary effect size or the average effect size. fourth, analysis of moderator variables. fifth, Evaluation of publication bias. The following will be discussed in greater depth, with an explanation of each topic. To gain access to the studies included in the meta-analysis, the researchers reviewed the databases of Google Scholar, Semantic Scholar, Research Gate, Open Journal System to search the keywords ‘vocabulary mastery’ and ‘Speaking ability’. These platforms' open access system allows everyone to participate detailed reviews on the studies were conducted to search for the fundamental variables of this study. Within this scope, the records contained r and n. r is a coefficient cost and n is the respondent. This research was conducted through online libraries such as Google Scholar, Semantic Scholar, Research Gate, with a total r = 21 samples data and n = 820. The following flowchart was used in the study to select the studies for the meta- analysis: Bangun and Simanjuntak The Effect of Vocabulary Mastery ……….. JOLLT Journal of Languages and Language Teaching, April 2022. Vol.10, No.2 | 214 Figure 1. Flowchart of Selection process of the Studies Instruments The analysis of this study uses Meta-analysis. the data r and n that have been collected are transferred to Microsoft Excel in order to get the effect-size and standard error using formulas. After finding the effect size and standard error values, the researchers conducted a meta-analysis using JASP software. For more details, see the table below. Table 1 Studies or Meta-Analysis materials Studies r n 1 (Uzer, 2017) 0,630 40 2 (Rahman, A., Multazim, A., Husna, A., & Hudayah, 2019) 0,99 40 3 (Aristi, Nina, 2017) 0,68 30 4 ((EKA, 2021) 0 35 5 (Nurmala Dewi, 2018) 0,538 60 6 (Harahap, n.d, 2021) 0,83 90 7 (ZAHARANI, 2017) 0,809 30 8 (Suryanto et al., 2021) 0 52 9 (Afifah, 2018) 0,665 79 10 (Sari, 2021) 0,873 44 11 (Jambari et al., 2021) 0,54 30 12 (Anry Ani, 2021) 0,423 22 13 (Nofal, 2017) 0,525 25 14 (Rahayu, 2021) 0,441 30 15 (Yuwandi, A. D., Azhar, F., & Marzuki, 2017) 0,83 23 16 (Laily, 2017) 0,294 30 17 (Putri, A., & Refnaldi, 2020) 0,703 30 18 (Fatimah, T., Purwanti, S. E., & Mustajib, 2019) 0,339 38 19 (Zaitun, Z., Hadi, M. S., & Zulfiana, 2020) 0,703 30 20 (Diyas Herdian Putra, I. Ikhsanudin, 2021) 0,19 30 21 (Taslim, T., Asrifan, A., Chen, Y., & Nurdania, 2019) 0,532 32 N 820 The studies discovered through the keywords ‘Vocabulary Mastery’ and ‘English-speaking ability’ The studies carried out between 2017-2021 The studies included in Google Scholar, Semantic Scholar, Research Gate, OJS databases The studies conducted at secondary education level The studies conducted to find out the effect of vocabulary mastery on English-speaking ability Bangun and Simanjuntak The Effect of Vocabulary Mastery ……….. JOLLT Journal of Languages and Language Teaching, April 2022. Vol.10, No.2 | 215 Data Analysis To calculate the effect sizes of each study, the first step that must be done is to collect the values of n and r, then create a table in Microsoft Excel. After collecting the data, the researcher finds out the effect size of each data to get an interpretation of the results. Using the formula to find [vz] of the variation of [z] with a purpose to know the standard error (SEz). So that the effect size of the correlation study can be analyzed. The following is the formula used for finding the effect size. 𝑧 = 0,5𝑥𝑙𝑛 1+𝑟 1−𝑟 vz = 0,5𝑙𝑛 1 𝑛−3 √𝑣𝑧 𝑆𝐸𝑧= Summary Effect or mean Effect Size After calculating the standard error and effect size of each data which is done through Ms. Excel, the data is converted into a meta-analysis data source by using JASP software to seek the heterogeneity, positive correlation of variables, and as well as to find out the level of standard error. The following below is the process of calculating the meta-analysis of the data. Figure 2. Summary Effect or Mean Effect Size Selecting the Model The heterogeneity test was employed in this meta-analysis to aid in the examination of study subjects with various parameters by displaying the degree of variability among the studies included. In addition, this heterogeneity test helped the researchers to see the heterogeneous distribution between studies that were included or studies that were not evaluated in this study. If there is heterogeneity in the studies, the causes of heterogeneity can be investigated using the study's characteristics. Study characteristics may be related to study heterogeneity, which can be interpreted using subgroup or meta-regression analysis. Following the determination of heterogeneity, the statistical model used to calculate effect sizes was chosen. The main approaches used in effect size calculations based on the level of inter-study variance differentiation are fixed and random effects models. Bangun and Simanjuntak The Effect of Vocabulary Mastery ……….. JOLLT Journal of Languages and Language Teaching, April 2022. Vol.10, No.2 | 216 Table 3 Heterogeneity Test results to determine the model to be used of meta-analysis Fixed and Random Effects Q df p Omnibus test of Model Coefficients 2.099 1 0.147 Test of Residual Heterogeneity 40272.855 20 < .001 Note. p -values are approximate. The findings of the research reveal that the 21-effect sizes of the studies examined are heterogeneous. (Q = 40272.855; p < 0,001. As a result, the random Effect modal is better suited for estimating the average effect size of the 21 studies examined. The analysis also identifies the possibility of investigating moderating variables that influence the relationship between student vocabulary mastery and English-speaking ability. After determining the heterogeneity, it was found that the result was heterogeneous. Thus to estimate the mean effect size or summary effect, Random Effect Model was utilized to obtain the Confidence Interval. Table 4 Summary Effect/Mean Effect Size Coefficients 95% Confidence Interval Estim ate Standard Error z p Lower Upper intercept 2.333 1.610 1.449 0.147 -0.823 5.489 Note. Wald test. The results of the analysis using a random (effect) model allow that there is a significant positive correlation between student's vocabulary mastery and English speaking ability (z = 1,449; p < 0,147; 95%Cl [[-0,823; 5,489]]. The effect of student's vocabulary mastery and English-Speaking ability is in the high category. (𝑟𝑅𝐸 =2,333). *r = 1 -3 (low); r = -5-3 (moderate); r = 5-10 (high) (Cohen, 1998). Based on the summary effect table, it is recommended to use a random effect model to estimate the summary effect value. The result is positive which can be seen in the Estimate column (2.333). This indicates that there is no negative sign, which means that the correlation between student's vocabulary mastery and English speaking ability is positive. As a result, the correlation between student vocabulary and English speaking ability is now positive, and the effect of the correlation between student vocabulary mastery and English speaking ability is categorized as high level. Bangun and Simanjuntak The Effect of Vocabulary Mastery ……….. JOLLT Journal of Languages and Language Teaching, April 2022. Vol.10, No.2 | 217 Forest plot Figure 3. Forest plot The picture above it explains that the value is from the highest 34.01 to the lowest value of 0.00. As seen in this forest plot, this spread of the dots shows the effect size, so the wider the spread, the higher the significance. Publication Evaluation Funnel Plot Figure 4. Funnel Plot It's difficult to tell whether the funnel plot is symmetrical or not based on the results. As a result, to determine whether or not the funnel plot is symmetrical, an Egger test is required. Bangun and Simanjuntak The Effect of Vocabulary Mastery ……….. JOLLT Journal of Languages and Language Teaching, April 2022. Vol.10, No.2 | 218 Table 5 Egger test Regression test for Funnel plot asymmetry (Egger's test) z p sei -0.459 0.646 As shown from the table of the Egger Test, the p > 0.05 confirms that the funnel plot is symmetrical. Thus, it can be concluded that there is no publication bias problem in this meta- analysis study. Table 6 Fail-safe N File Drawer Analysis Fail-safe N Target Significance Observed Significance Rosenthal 32985.000 0.050 <.001 From the table above, the K= 21, so 5K+10 = 115. The fail- safe N value obtained is 32985.000, with a significant target of 0.05 and p < 0.001. Because the safe value of N > 5K+10, it can be concluded that there is no publication bias problem in the meta-analysis study. RESEARCH FINDINGS AND DISCUSSION Research Findings The purpose of this study is to determine the magnitude of vocabulary mastery's effect on English-speaking ability. In each meta-analysis study included, the effect size is a factor that indicates how much the independent variable effects the dependent variable positively or negatively. Table 7 Variable Effects on Students’ Speaking Achievement Studies r n z vz sez 1 (Uzer, 2017) 0,630 40 0,660 0,027 0,164399 2 (Rahman, Multazim, Husna, & Hudayah, 2019) 0,99 40 34,407 0,027 0,164399 3 (Aristi, Nina, 2017) 0,68 30 0,811 0,037 0,19245 4 (EKA, 2021) 0 35 0,000 0,031 0,176777 5 (Nurmala Dewi, 2018) 0,538 60 0,466 0,018 0,132453 6 (Harahap, n.d, 2021) 0,83 90 1,777 0,011 0,107211 7 (Zaharani, 2017) 0,809 30 1,552 0,037 0,19245 8 (Suryanto et al., 2021) 0 52 0,000 0,020 0,142857 9 (Afifah, 2018) 0,665 79 0,761 0,013 0,114708 10 (Sari, 2021) 0,873 44 2,471 0,024 0,156174 11 (Jambari et al., 2021) 0,54 30 0,469 0,037 0,19245 12 (Anry Ani, 2021) 0,423 22 0,306 0,053 0,229416 13 (Nofal, 2017) 0,525 25 0,444 0,045 0,213201 14 (Rahayu, 2021) 0,441 30 0,327 0,037 0,19245 15 (Yuwandi, Azhar, & Marzuki, 2017) 0,83 23 1,777 0,050 0,223607 16 (Laily, 2017) 0,294 30 0,183 0,037 0,19245 17 (Putri, A., & Refnaldi, 2020) 0,703 30 0,896 0,037 0,19245 18 (Fatimah, Purwanti, & Mustajib, 2019) 0,339 38 0,221 0,029 0,169031 19 (Zaitun, Z., Hadi, M. S., & Zulfiana, 2020) 0,703 30 0,896 0,037 0,19245 20 (Diyas Herdian Putra, I. Ikhsanudin, 2021) 0,19 30 0,107 0,037 0,19245 21 (Taslim, Andi Asrifan, Yan Chen, 2019) 0,532 32 0,456 0,034 0,185695 820 Bangun and Simanjuntak The Effect of Vocabulary Mastery ……….. JOLLT Journal of Languages and Language Teaching, April 2022. Vol.10, No.2 | 219 DISSCUSSION In this global era, English plays an important role as a communication language used in many areas of life, including trade, bilateral relations, politics, science, and technology, among many others. People use English to communicate and share information with one another. When trying to understand what someone is saying, everyone must master the vocabulary, grammar, and pronunciation of words in order for it to be clear and not misunderstood. Speaking is another type of spoken language that is used to express ideas and emotions (Jambari et al., 2021). Vocabulary knowledge has been seen as an initial skill that must be mastered by EFL learners to improve other language skills. Fundamentally, vocabulary knowledge is a prerequisite for most other language skills (Dakhi & Fitria, 2019) Several studies on vocabulary and speech have been undertaken in the past. (Uzer, 2017)conducted one of the most widely cited studies, in which he investigated the relationship between vocabulary mastery and improved speaking skills in EFL students in senior high school. The statistical connection between them was 0.630, indicating that studying vocabulary plays a major influence in improving students' speaking skills. In this study, the first outcome of the data analysis is the effect of vocabulary mastery on English-speaking ability. The effect of the correlation between student vocabulary mastery and English speaking ability was classified as high level/positive impact in this study. The second outcome is to determine whether there is any publication bias from previous studies. After the analysis was carried out from the Egger Test table, p > 0.05; it confirms that the funnel plot is symmetrical which means there is no problem of publication bias in this meta-analysis. This finding is supported in table six, that K= 21, so 5K+10 = 115. The fail-safe N value obtained was 32985,000, with a significant target of 0.05 and p < 0.001. Since the safe value of N > 5K + 10, it can be concluded that there is no problem of publication bias in the meta-analysis study. After the researcher conducted an analysis using the formula of (Cohen 1998) to calculate the correlation it was found that there was a significant positive relationship between students' vocabulary mastery and English speaking ability. Using a random effect model to estimate the summary effect value is recommended based on the summary effect table. In the Estimate column, the outcome is positive (2.333). This means that the correlation between a student's vocabulary mastery and English speaking ability is positive. As a result, the correlation between student vocabulary and English speaking ability is positive. Based on the outcomes of the study that occurred from the data analysis, it is very clear that language teachers, in teaching English speaking subjects, need to develop certain strategy with useful techniques in it to enhance students' understanding and knowledge in using the right words or phrases because the ability to speak will never be improved if it is not accompanied by an established vocabulary knowledge. CONCLUSION The study can be inferred that there is no publication bias based on researchers' evaluations using a funnel plot or Egger test, as well as fail-safe N analysis or fail drawer analysis. The random effect model performed better in estimating the mean effect size of the 21 studies examined. The results of the analysis also revealed that moderating variables that influence the effects of vocabulary mastery on english-speaking ability should be investigated further. ACKNOWLEDGEMENT First and foremost, we would like to express our deepest gratitude to God Almighty for allowing us to complete this study. We whole-heartedly dedicate this study to English Education study program has supported us in terms of providing us with useful web platforms to select our studies. We do appreciate the value of time that our family gave to exhort and propel us to finalize this study. Additionally, we would like to sincerely thank the readers for Bangun and Simanjuntak The Effect of Vocabulary Mastery ……….. JOLLT Journal of Languages and Language Teaching, April 2022. Vol.10, No.2 | 220 some criticism and suggestions for the success of this meta-analysis study. Hopefully this article can be of great use to enthusiastic readers and future researchers. REFERENCES Afifah, N. (2018). 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