On the Effect of Content-Based Instruction over Iraqi Intermediate EFL High School Learners’ Reading Comprehension and Vocabulary Learning

Abstract

Learning vocabulary is crucial to acquiring a second language. This study examined the effects of implicit and explicit vocabulary instruction on immediate and delayed memory of content words among Iraqi learners of English. The participants were 40 high school students, divided into experimental group (implicit guidance) and control group (explicit guidance). These treatments were conducted over 20 sessions in science classes. A pretest, immediate posttest, delayed posttest, and reading comprehension test were administered. Results showed that both implicit and explicit instruction resulted in significant vocabulary increases from pretest to posttest. However, the explicit group made larger immediate gains but also larger losses on the delayed test, whereas the implicit group retained more words in the long run. The experimental group also performed significantly better on a reading comprehension test. This study proposes a combination of implicit and explicit techniques, with implicit methods being more suitable for long-term storage.