Thai Secondary School Learners’ Knowledge of Prefixes and Suffixes and their Relationship with Vocabulary Size

Abstract

Vocabulary plays a critical role in the overall language skills of second and foreign-language learners. Thus, this cross-sectional study investigated the relationship between vocabulary size and knowledge of prefixes and suffixes in Thai high school learners. This study also examined how Thai EFL high school learners knew English affixes, including prefixes and suffixes. 595 high school participants from a provincial setting were given three vocabulary knowledge tests. These tests included the Vocabulary Level Test (VLT), the Word Parts Level Test (PWLT), and the Prefix- Suffix Knowledge Test (PST). The data were collected using the SPSS software. Both descriptive and inferential statistics were conducted to analyze the data. The results showed that Thai EFL high school learners had poor knowledge of vocabulary size. The analysis of the findings also indicated that Thai EFL high school learners had a poor understanding of English prefixes and suffixes. In addition, the analysis of the results revealed a moderate relationship between Thai high school learners’ vocabulary size and knowledge of English affixes. Furthermore, the analysis of the findings indicated that Thai high school learners’ understanding of English affixes and vocabulary size developed following their education levels. These findings suggest that Thai high school learners’ vocabulary size and knowledge of English prefixes and suffixes develop when their exposure to such knowledge increases. The present results could raise awareness among practitioners, especially teachers, that English affixes, prefixes, suffixes, and word formations should focus more on classroom practices. Other related implications and recommendations for future studies are also given.

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