Evaluation of Vocabulary Use in EFL Textbooks: Evidence From Curriculum Words

This study aims to evaluate the use of vocabulary in a local EFL textbook series designed for middle-school students. To accomplish this, two criteria were used: curriculum words and British National Corpus (BNC) high-frequency words. The study examines two features of the textbook’s vocabulary use: (1) representation and repetition of curriculum and BNC high-frequency word lemmas and (2) lexical sophistication measured by the proportion of non-curriculum and BNC low-frequency word lemmas. The results indicate that the textbook series adequately represents curriculum words (99.9%) but has a medium representation of BNC high-frequency words (74.6%). Additionally, there is a lack of word repetition in the textbook series, with 16.5% of curriculum words being used only once. Lexical sophistication, as measured by non-curriculum words, increases gradually as grade levels increase. These results suggest that using different evaluation criteria could produce different outcomes from the same data. Furthermore, compared with word lists derived from native language data, curriculum words provide a more reliable criterion for evaluating middle-school EFL textbooks targeting learners with low–intermediate language proficiency.