Fine-tuning word meanings through mobile app and online resources: A case study of strategy use by a hyperpolyglot Andrew D. Cohen a, * , Isobel Kai-Hui Wang b a Professor Emeritus, University of Minnesota,1555 Lakeside Drive #182, Oakland, CA, 94612, USA b ELT Research and Methodology, Institute of English Studies, University of Graz, Liebigasse 9, Graz, 8010, Austria article info Article history: Received 22 March 2019 Received in revised form 13 July 2019 Accepted 15 July 2019 Available online 16 July 2019 abstract The purpose of this study was to investigate a hyperpolyglot's strategies for fine-tuning his understanding of Chinese vocabulary through mobile apps, online programs, and in- teractions with a tutor. Videotaped verbal reporting revealed that the subject used stra- tegies for (1) managing vocabulary resources e planning, organizing, and monitoring/ evaluating their use, and for (2) processing the information in the resources e finding word equivalents in Chinese for English words, fine-tuning the word meanings and then verifying them. He predominantly used strategies either in sequence or in pairs, some- times separately, and only occasionally in clusters. While he was successful at fine-tuning 57% of the vocabulary items through accessing selected resources, his fine-tuning efforts still were unsuccessful 43% of the time. The effectiveness of fine-tuning depended on the subject's ability to find the information he needed, to orchestrate the various aspects of word knowledge, and to monitor and evaluate his performance. This case study with one highly experienced language learner applied a close-up lens to the process of vocabulary fine-tuning, and provided insights for researchers and teachers regarding strategies for accessing technology aimed at enhancing vocabulary knowledge. © 2019 Elsevier Ltd. All rights reserved. 1. Introduction While the burgeoning of mobile apps and online programs has revolutionized the learning and use of languages, one could ask whether language learner strategy (LLS) use has kept pace with these technological advances. Given these new interactive learning environments, researchers and practitioners have been called to rethink the role of LLS (Zhou & Wei, 2018). The purpose of this study was to investigate the strategies of a highly accomplished language learner when making use of mobile apps and online dictionary/translation programs in order to arrive at an accurate understanding of word meanings in context. The study applied a close-up lens to the process of fine-tuning verb meanings with the goal of gaining insights into how to make better use of LLS for this purpose. The investigation looked at vocabulary fine-tuning strategies employed by a hyperpolyglot who was studying his 13th language, Mandarin Chinese (henceforth referred to simply as “Chinese”), where word meanings often diverged dramatically from English, his first language (L1) and the language that he thought in when writing Chinese sentences for a weekly blog. What prompted the idea for the study was that this learner was regularly engaged in accessing dictionary and translation * Corresponding author. E-mail addresses: adcohen@umn.edu (A.D. Cohen), kaihui.wang@uni-graz.at (I. Kai-Hui Wang). Contents lists available at ScienceDirect System journal homepage: www.elsevier.com/locate/system https://doi.org/10.1016/j.system.2019.102106 0346-251X/© 2019 Elsevier Ltd. All rights reserved. System 85 (2019) 102106