Direct Vocabulary Instruction: The Effects of Contextualised Word Families on Learners' Vocabulary Acquisition

Acquiring vocabulary is one of the biggest challenges in learning the second language in Malaysia. Classroom research has ascertained that students can experience a great improvement in their vocabulary growth if they are given exposure to meaningful input even with the absence of direct instruction (Lightbrown & Spada, 2006). However, other studies have also revealed that without direct vocabulary instruction (DVI) students could not make further progress in some features of the second language. In view of these conflicting findings, this study aims to examine the effects of a systematic and structured proposed contextualized word family model of DVI on students' vocabulary acquisition. It also aims to answer its research question on whether there are any significant differences between students' vocabulary size before and after DVI using contextualised word families based on proficiency levels. This present study employs a quasi-experimental design whereby the data collection is done in a normal classroom condition using Laufer and Nation's (1999) Productive Vocabulary Levels Test (PVLT) at 2000-word level (Test A and Test B). The data obtained from the pre-test (Test A) and post-test (Test B) scores of the PVLT was computed using paired samples t-tests. It was found that there was a statistically significant difference between learners' vocabulary size in the pre-test and post-test after direct instruction using the contextualised word families for two and a half months. Therefore, the results rejected the null hypothesis of no difference and accepted the research hypothesis that there was a statistically significant difference between learners' vocabulary size before and after the treatment. The findings reveal some important implications for instructional practices, new knowledge in L2 vocabulary acquisition and recommendations for future research. (C) 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license