The present study examines the effects of 3 kinds of glosses—first-language (L1) Chinese glosses plus second-language (L2) English example sentences, L1 in-text glosses, and L1 marginal glosses—in comparison with a no-gloss condition in reading an English passage, to explore whether providing glosses can facilitate reading comprehension and vocabulary acquisition. A total of 135 undergraduate business and engineering students at 4 English proficiency levels studying at a technical university in Taiwan completed 1 vocabulary pretest, 1 reading session, 1 posttest, and 2 delayed vocabulary recall tests. The study found that L1 glosses helped subjects learn new words and review learned words. Learners’ retention declined between the immediate and the 1st delayed recall tests. However, between the 1st and 2nd delayed recall tests, a slight increase in retention was observed for all groups. Unexpectedly, reading comprehension did not improve significantly. Additionally, a questionnaire queried learners’ experience using glosses during reading
