The Effect of Textual Marginal Glosses on Incidental Vocabulary Retention of Iranian EFL Students

The present study investigated the effect of marginal glosses (both L1 and L2) on incidental vocabulary learning of EFL learners. The subject pool consisted of 154 third-semester Iranian students enrolled at Azad University, Central Branch. After administering a proficiency test, 90 homogeneous students were assigned to two experimental groups (X1 & X2) and one control group. Afterwards, a 50 -item pretest was administered to verify students’ unfamiliarity with the intended target words to be learned later. Then the treatment began and X1 received L1 glosses and X2 received L2 glosses, and the control group received no glosses. Finally, a post-test, the same as the pre-test with 10 familiar items deleted, was administered to the three groups. A one-way ANOVA indicated that learners with access to L2 or L1 marginal glosses demonstrated significantly greater retention of word meanings. Additionally, a further analysis known as the Tukey test was conducted to pinpoint exactly where the differences exist in a pair-wise way. The results of this analysis showed that X2 outperformed X1 and the control group