Vocabulary is a fundamental component in mastering a foreign language, especially English. It serves as the foundation for communication, allowing learners to express ideas, understand others, and engage effectively in both spoken and written interactions. According to Susanto (2017), vocabulary mastery is a crucial aspect in foreign language learning and significantly influences learners’ comprehension skills. Saputri (2017) further asserts that vocabulary is the most important aspect of language acquisition, and students must first acquire sufficient vocabulary before progressing to other language skills such as reading, speaking, listening, and writing.

However, national data shows that English performance among Indonesian elementary students remains low. According to the 2022 National Assessment Report by the Ministry of Education and Culture, only 37% of Grade 5 students achieved a “proficient” score in English vocabulary, indicating a widespread struggle at the foundational level. The primary challenge lies in the low retention of new words among students, often due to lack of meaningful context and the use of monotonous, rote memorization methods. As Thornbury (2002) pointed out, retaining vocabulary is difficult without contextual reinforcement and active engagement.

During a preliminary visit to SD Negeri 10 Jarai in Lahat Regency, South Sumatra, the researcher conducted discussions with the English teacher, Mr. Anton, S.Pd., and observed classes in Grades V-A and V-B. The students exhibited limited vocabulary mastery, which hindered their progress in learning English. Most of them were required to memorize long word lists, without engaging activities, which led to boredom, low participation, and demotivation.

In response, the researcher proposed integrating a digital-based solution through the English Vocabulary Application (EVA)—a mobile app offering interactive games, colorful visuals, and audiovisual materials designed to create an enjoyable vocabulary learning experience. The shift to mobile and gamified learning is aligned with current trends in education technology. Dewi (2012) found that Aplikasi Kosakata Bahasa Inggris Mendorong Penguasaan di Kalangan Siswa Kelas 5 SD Arimbawa (2021) defined learning media as tools that help teachers deliver learning content more effectively.

Recent studies support this direction. A quasi-experimental study by Ginting (2023) showed that EVA significantly improved vocabulary scores in junior high school students, with an effect size of 0.78, indicating a high practical impact. Likewise, Ramadhani et al. (2024) demonstrated that gamified vocabulary apps increased vocabulary test performance among Grade 6 students in urban schools by 22.5% on average. However, these studies were mostly conducted in urban or secondary-level contexts.

Research Gap:To date, no quasi-experimental study has investigated the use of the EVA application at the elementary (SD) level in rural areas in Indonesia, despite the high potential of digital tools for this age group.

Research Purpose: Therefore, this study aims to determine the effect of the English Vocabulary Application (EVA) on the vocabulary acquisition of fifth-grade students at SD Negeri 10 Jarai. The research specifically focuses on the integration of mobile technology and gamification strategies to improve English learning outcomes in a rural elementary school context.

Novelty: This study offers a novel combination of EVA, gamified learning, and a quasi-experimental design, applied specifically in the underexplored context of a rural Indonesian elementary school. This approach provides new insights into how digital learning tools can address foundational vocabulary issues at the primary education level.

This study employed a quasi-experimental research design with a non-equivalent control group, aiming to determine the effectiveness of the English Vocabulary Application (EVA) in improving vocabulary mastery among fifth-grade students at SD Negeri 10 Jarai. This design was chosen due to practical constraints in implementing random assignment within the school setting, where class divisions were already established administratively. As Creswell (2012) and Fraenkel et al. (2015) explain, quasi-experimental designs are suitable for educational settings where true randomization is not feasible but a comparison between intervention and control groups is still desired to infer causal relationships.

The sample consisted of two intact classes: Class VA as the experimental group (32 students), who were taught using EVA, and Class VB as the control group (31 students), who received conventional instruction using printed pictures and flashcards. Both groups underwent a pre-test and post-test to assess their vocabulary acquisition before and after the intervention.

The teaching procedure for the experimental group included a series of interactive activities through the EVA, such as vocabulary games, visual-audio word matching, thematic quizzes, and contextual sentence-building tasks. The control group followed conventional teaching strategies, including visual aids (pictures, flashcards), oral repetition, and teacher-led explanation. The intervention was conducted over eight sessions (2 sessions/week for 4 weeks), culminating in a post-test to measure learning outcomes.

The data collection instruments were vocabulary tests administered both before (pre-test) and after (post-test) the intervention. Each test consisted of 30 items, including multiple-choice questions (10 items), picture labeling (6 items), word-picture matching (8 items), and fill-in-the-blank vocabulary tasks (6 items). The instruments were first validated by two English education experts for content validity, and reliability testing was conducted using Cronbach’s Alpha via SPSS version 26, yielding an alpha value of 0.84, which indicates a high level of internal consistency.

Data analysis involved two main techniques:

a)To compare the pre-test and post-test results within each group, paired sample t-tests were used. b) Independent sample t-tests to compare the experimental and control groups' post-test results.

Hypothesis testing was conducted at a 5% significance level (α = 0.05). Additional analyses included effect size (Cohen’s d) to determine the magnitude of the intervention’s impact, in addition to assumption testing for homogeneity of variances (Levene's Test) and normality (Shapiro-Wilk test).

This methodology allowed for a structured and rigorous examination of how mobile-based vocabulary learning tools compare with traditional instructional approaches in the context of elementary-level English education in a rural setting.

H ASIL DAN P EMBAHASAN

This study aimed to investigate the effectiveness of the English Vocabulary Application (EVA) in improving the vocabulary mastery of fifth-grade students at SD Negeri 10 Jarai. The study was conducted over eight meetings involving two groups: an experimental group (class VA, 32 students) and a control group (class VB, 31 students). Both groups were given a pre-test and post-test consisting of 35 multiple-choice questions to assess their vocabulary comprehension before and after the treatment.

Descriptive statistical analysis showed a clear improvement in vocabulary mastery in both groups. In the experimental class, the mean score increased from 54 in the pre-test to 85 in the post-test, with standard deviation decreasing from 10.59 to 7.90. This indicated not only improved performance but also greater consistency among students’ scores. he num er of students passing the voca ulary test (score ≥ 60) rose from 9 students in the pre-test to all 32 students in the post-test.

In the control class, the pre-test mean score was 60, and the post-test mean score also reached 85. While the improvement appeared comparable at a glance, further analysis revealed that the standard deviation dropped from 13.99 to 7.34, indicating improvement, but with less pronounced gains than in the experimental group. The number of students failing in the pre-test (approximately 6–8 students) was reduced to zero in the post-test.

To examine the significance of these differences, a series of statistical analyses were conducted using SPSS version 25. A paired sample t-test for the experimental group revealed a statistically significant improvement (sig. 2- tailed = 0.000 < 0.05), confirming that the use of EVA had a positive impact on students’ voca ulary mastery. Similarly, the control group also showed a statistically significant improvement (sig. 2-tailed = 0.000), although with a slightly lower t-obtained value compared to the experimental group.

The independent sample t-test comparing the post-test scores between the two groups yielded a t-obtained value of 10.5860, which was greater than the t-table value of 7.3392 at df = 60 and a significance level of 0.000. This result confirmed a statistically significant difference between the experimental group taught using EVA and the control group taught through conventional methods, leading to the rejection of the null hypothesis ( ₀) and acceptance of the alternative hypothesis ( ₁). herefore, it can e concluded that the use of the English Vocabulary Application significantly improved the vocabulary mastery of students.

These findings align with previous studies emphasizing the importance of interactive and contextual vocabulary learning. The effectiveness of EVA can be attributed to its integration of images, sounds, and gamified content, which supported students in retaining vocabulary more easily and made the learning process more engaging. his is consistent with Mayer’s (2020) theory that multimedia learning, particularly through visual and auditory stimuli, enhances conceptual understanding. Moreover, the o served improvements also support Schmitt’s (2008) view on the crucial role of motivation and strategy in vocabulary acquisition.

In summary, the use of EVA as a vocabulary learning tool proved to be significantly more effective than traditional teaching methods. Not only did it help students achieve higher test scores, but it also fostered active engagement and consistency in performance. This suggests that mobile-based learning applications, when used effectively, can be a valuable asset in elementary education, especially in the context of English as a foreign language.

This study investigated the impact of using an English vocabulary application to improve vocabulary mastery among fifth-grade students at SD Negeri 10 Jarai. The research included two classes: an experimental class (32 students) and a control class (31 students). Students in both groups underwent a pre-test and post-test to evaluate their vocabulary comprehension. The intervention was conducted over eight meetings.

The descriptive statistical analysis showed that the experimental class improved significantly. The mean score increased from 54.00 in the pre-test to 85.00 in the post-test. Moreover, the standard deviation decreased from 10.59 to 7.90, indicating more consistent student performance. In contrast, the control class had a mean pre-test score of 60.00 and a post-test score of 85.00, with a standard deviation decreasing from 13.99 to 7.34. Although both groups showed improvement, the experimental class demonstrated a stronger gain from a lower baseline.

A paired sample t-test revealed a significant difference in students' vocabulary mastery before and after the intervention in both classes. The significance value for both the experimental and control groups was 0.000, which is below the threshold of 0.05. However, the magnitude of improvement was more pronounced in the experimental class.

The independent sample t-test compared the post-test results between the experimental and control classes. The analysis revealed a significant difference in favor of the experimental group, supporting the hypothesis that the English vocabulary application was effective. The t-obtained value was 10.5860, significantly exceeding the critical t-table value of 7.3392.

The interpretation of these findings highlights that using an English vocabulary application as a teaching medium positively affected students' learning outcomes. Students in the experimental class not only improved theiraverage scores but also showed a more homogeneous distribution of performance. This suggests that the application helped lower-achieving students catch up with their peers.

In conclusion, integrating technology-based learning through an English vocabulary application enhanced students’ voca ulary comprehension effectively. his method can e recommended for broader implementation and further research. The study confirms that technological integration in the classroom offers a promising alternative to conventional vocabulary teaching methods.

This chapter presents the findings of the study and discusses their implications. The aim was to evaluate the effectiveness of the English Vocabulary Application (EVA) in improving vocabulary mastery among fifth-grade students at SD Negeri 10 Jarai. The data were collected through pre-tests and post-tests administered to two groups—an experimental group taught using EVA and a control group taught using traditional methods.

Based on the findings and analysis conducted in this study, it can be concluded that the use of the English Vocabulary Application (EVA) significantly improves students’ vocabulary mastery. This research, conducted using a quasi-experimental design during the 2024/2025 academic year, involved fifth-grade students of SD Negeri 10 Jarai. The study aimed to determine the effectiveness of EVA in enhancing vocabulary acquisition compared to conventional teaching methods.

The results indicated that students in the experimental group who were taught using EVA showed notable improvement in vocabulary comprehension, accompanied by higher consistency and engagement. These findings confirm that integrating mobile-based digital tools in language instruction can lead to more effective learning outcomes than traditional approaches. The study, therefore, achieves its main objective: to investigate the effectiveness of the English Vocabulary Application (EVA) in improving vocabulary mastery among fifth-grade students at SD Negeri 10 Jarai.

In practical terms, this study offers valuable implications for elementary English teachers and educational institutions. Teachers are encouraged to incorporate applications like EVA into classroom practice, ideally within 15–20 minute segments of a lesson plan (RPP), and combine them with other student-centered techniques such as storytelling or role-playing. Schools should also consider supporting infrastructure and training for the effective integration of educational technology, especially in rural or underserved contexts.

For future research, it is recommended to explore long-term retention effects of using EVA, examine its applicability across different grade levels or subject areas, and investigate how EVA might be integrated into cross-curricular learning. Studies could also assess teacher perceptions and challenges in adopting mobile learning tools to further refine implementation strategies.

In conclusion, the English Vocabulary Application proves to be a practical, engaging, and pedagogically sound innovation for improving vocabulary learning among elementary school students. Beyond its academic contribution, this study underscores the importance of technology integration in fostering a more dynamic and inclusive language learning environment.

The researcher would like to express sincere gratitude to all parties who contributed to the completion of this research.

First and foremost, deepest thanks are extended to the Head of SD Negeri 10 Jarai, as well as the English teacher Mr. Anton, S.Pd., for granting permission and providing support throughout the data collection process. The cooperation and enthusiasm of the fifth-grade students who participated in this study are also greatly appreciated.

The researcher would also like to thank academic advisors and lecturers at STKIP Muhammadiyah, Program Studi Bahasa Inggris, whose guidance and constructive feedback greatly assisted in the refinement of this research.

Finally, heartfelt appreciation is given to the researcher's family and peers for their moral support, encouragement, and motivation throughout the research process.

This research would not have been completed successfully without the help and support of all the individuals mentioned above.