This longitudinal study investigates the effect of mode of reading on the incidental learning of collocations and factors that affect learning. One hundred Vietnamese pre-intermediate learners of English as a foreign language (EFL) were assigned to either an experimental group or a control group (no treatment). In 9 weeks, the experimental group read three graded readers containing 32 target collocations in three counterbalanced reading modes: reading-only, reading-while-listening, and reading with textual input enhancement (i.e., underlining). Learning gains were measured by a form recall pretest and delayed posttest. The results showed that reading mode had a significant effect on incidental collocation learning. Reading with textual input enhancement resulted in significantly higher learning gains than the other reading modes. Reading-while-listening was also more beneficial for collocation learning than reading-only. Learners’ prior vocabulary knowledge and congruency of collocations were significant predictors of the learning gains.

This article reports the results of two experiments which compared the effects of reading-only, reading-while-listening, and reading with textual input enhancement (i.e. underlining) on Vietnamese English as a foreign language (EFL) learners’ learning of three aspects of vocabulary knowledge: form recognition, form recall, and meaning recall. Sixty Vietnamese EFL learners (32 beginner and 28 intermediate learners) were assigned to one of three experimental conditions: reading-only, reading-while-listening, or reading with textual input enhancement. During four weeks, all learners read four graded readers in their condition groups. Tests of target words were administered three times: one week before the reading (pretests), immediately after the reading (immediate posttests), and one week after the reading (delayed posttests). To gain more insights into the learners’ perspectives, follow-up semi-structured interviews were conducted. The results showed that the three reading modes resulted in word learning gains for the three word knowledge aspects tested. However, reading with textual input enhancement resulted in significantly more vocabulary learning than reading-only, while the reading-while-listening and reading-only groups did not differ significantly. In addition, form recognition had the largest gains while form recall the smallest.

This review paper aims to provide an overview of vocabulary in English language learning, teaching, and testing in Vietnam. First, we review studies on the vocabulary knowledge of Vietnamese EFL learners. Recent research evaluating different aspects of vocabulary knowledge shows that Vietnamese EFL learners generally have limited knowledge of both single words and formulaic language. Next, we discuss contemporary approaches to teaching vocabulary in Vietnam to reveal current issues and provide relevant recommendations. Empirical studies on Vietnamese EFL learners’ vocabulary acquisition are also discussed with an aim to shed light on how vocabulary can be acquired by Vietnamese EFL learners and subsequently draw important pedagogical implications. In addition, we look into the lexical component of high-stakes English tests in Vietnam, calling for more attention to the lexical profiles and lexical coverage of those tests. Finally, we provide concluding remarks and research-informed recommendations for EFL vocabulary learning and teaching in Vietnam to elaborate on how vocabulary can be effectively learned and taught.