Measuring English Vocabulary Size and Exploring Factors Affecting Vocabulary Learning in University Students

Background and Aims: Understanding the factors that influence vocabulary acquisition is crucial for enhancing language learning in higher education. This study investigates the vocabulary size of students within the Faculty of Humanities and Social Sciences at Sisaket Rajabhat University, exploring the role of major-specific differences and motivation in vocabulary learning. Methodology: The sample group consisted of 169 third-year students from the Faculty of Humanities and Social Sciences at Sisaket Rajabhat University. Data were collected through a vocabulary size test and a questionnaire, and the results were analyzed using the SPSS 17.0 statistical software. The reliability of the instruments was assessed (Cronbach's alpha), as well as percentages, mean scores, and standard deviations. Results: The findings revealed that students had an average vocabulary size of 4,490 words out of a total of 14,000 words, or 26.54%. The highest score was observed at the 1,000-word level, with an accuracy rate of 46.70%, which gradually declined at higher levels, reaching a low of 13.80% at the 14,000-word level. Notably, students majoring in Business English and language-related majors, such as Japanese and Chinese, scored higher than students in other majors at all levels. A more detailed examination of factors affecting vocabulary learning motivation indicated that overall, students had a high level of motivation to learn vocabulary. Factors such as presenting vocabulary in real-life contexts, the difficulty level of vocabulary, and learning in a relaxed atmosphere all contributed to students' motivation to learn English vocabulary. Conclusion: The results indicate that students at Sisaket Rajabhat University have an average vocabulary size of 4,490 words, representing 26.54% of the total target vocabulary. Students performed best at the 1,000-word level, but accuracy decreased at higher levels, with the lowest score at the 14,000-word level. Notably, those majoring in Business English and language-related fields such as Japanese and Chinese had higher vocabulary scores across all levels. Additionally, students exhibited strong motivation to learn vocabulary, with key motivating factors including the use of real-life contexts, vocabulary difficulty, and a relaxed learning environment.