A Systematic Self-Review of Studies on EFL Vocabulary: Teaching, Assessment, Learning Outcomes, and AI Translation Quality

Abstract

This study presents a systematic self review (SR) of the author’s research on vocabulary teaching and learning published between 2006 and 2025. The corpus comprises forty three studies organized into five thematic clusters: (i) what vocabulary teaching and learning entail; (ii) the integration of technology (mind mapping, online tasks, web based learning, mobile applications, and YouTube videos) into vocabulary instruction; (iii) vocabulary assessment; (iv) vocabulary learning outcomes, with a focus on learners’ difficulties in acquiring and translating lexical features such as phoneme–grapheme correspondences, morphological patterns, pronunciation, plurals, polysemes, collocations, pronouns, and technical terms; and (v) the use of AI tools for transliterating and translating terminology. Across these clusters, findings show that vocabulary development is a multi component process shaped by phonological, morphological, semantic, and contextual factors. Effective instruction consistently emphasizes lexical associations, structured scaffolding, and multimodal input, while technology enhances learning only when aligned with sound pedagogical principles. Studies on vocabulary assessment demonstrate that reliable evaluation requires multi level tasks capable of capturing both the breadth and depth of vocabulary knowledge, moving toward a more comprehensive performance based measures. Studies on learner difficulties and translation errors reveal persistent challenges with phoneme–grapheme correspondences, morphological complexity, pronunciation accuracy, collocational competence, and the interpretation of plurals and polysemes. A strong tendency toward literal translation was noted to be a recurring pattern, particularly when learners encounter unfamiliar lexical or cultural features. Studies on AI assisted transliteration and translation further highlight the limitations of current systems in handling specialized terminology, morphological variation, and context dependent meanings. Collectively, the findings underscore the need for pedagogical designs that foster lexical depth rather than surface memorization, and for integrated approaches that connect teaching, assessment, and translation training. The significance of this SR lies in its comprehensive synthesis of a large, thematically diverse corpus produced over twenty years by a single researcher. By mapping the evolution of vocabulary related scholarship across instructional, technological, assessment based, and translational dimensions, this SR provides a coherent framework that advances understanding of how vocabulary is acquired and operationalized in EFL contexts. It also offers a consolidated foundation for future research, curriculum development, and instructional innovation in vocabulary studies.