This paper presents data capturing Korean university students’ familiarity with English online acronyms, examines factors that may predict this familiarity, and presents an explicit instruction intervention involving vocabulary knowledge of online acronyms. The Vocabulary Size Test (VST) measured stude nts’ vocabulary size, while a self-report survey measured social media engagement and the percentage of engagement that occurred in English. The Vocabulary Knowledge Scale (VKS) measured initial familiarity and gains in vocabulary knowledge. The results suggest that English learners in Korean universities are not well-acquainted with English online acronyms, but that receptive vocabulary size and English-language social media engagement may offer some predictive power regarding their level of familiarity. An explicit treatment of acronym expansions and their uses resulted in a significant and robust gain in vocabulary knowledge, suggesting that explicit instruction of online acronyms may improve digital literacy and comprehension of computer-mediated communication (CMC) more effectively than simply relying on incidental gains through repeat exposures over time.

1. INTRODUCTION
2. LITERATURE REVIEW
    2.1. Computer-Mediated Communication and Language Change
    2.2. Vocabulary Acquisition Via CMC
    2.3. Research Questions
3. METHODOLOGY
    3.1. Selection of the Target Vocabulary
    3.2. Participants
    3.3. Survey Instruments
    3.4. Data Collection
    3.5. Analysis of the Data
4. RESULTS
5. DISCUSSION
6. CONCLUSION
REFERENCES
APPENDIX A
APPENDIX B

• Dennis Laffey(Assistant Professor, Department of English Language and Literature, Pukyong National University; 45 Yongso-Ro, Busan 48513, Korea)