Enhancing L2 vocabulary acquisition through implicit reading support cues in e-books Yeu-Ting Liu and Aubrey Neil Leveridge Yeu-Ting Liu is an associate professor in the Department of English at National Taiwan Normal University. His current research projects focus on bilingual lexical processing, cognitive development in advanced second language (L2) learners and cognitive aspects of computer-assisted L2 learning. Aubrey Neil Leveridge is a lecturer at Vantage College, University of British Columbia. His current research projects focus on computer-assisted language learning. Address for correspondence: Dr.Yeu-Ting Liu, Associate Professor, Department of English, National Taiwan Normal University, No. 162, Section 1, HePing E. Road, Da’an District, Taipei 10610, Taiwan. Email: yeutingliu@ ntnu.edu.tw Abstract Various explicit reading support cues, such as gloss, QR codes and hypertext annotation, have been embedded in e-books designed specifically for fostering various aspects of language development. However, explicit visual cues are not always reliably perceived as salient or effective by language learners. The current study explored the efficacy of implicit reading support cues—cues that are imperceptible to second-language (L2) readers during their L2 digital reading—for promoting L2 vocabulary acquisition. Results suggest that subliminal formal priming—being one type of implicit reading support cues—helped L2 readers significantly improve their form-meaning vocabulary knowledge through e-book reading. In particular, subliminal formal priming was more effective when the digital content, including the text and relevant illustration, was pre- sented to L2 readers simultaneously, rather than incrementally. The results have impor- tant implications vis-à-vis the need for the inclusion of implicit reading cues, and the optimal digital input presentation mode for enhancing L2 vocabulary gains. Introduction E-books often appear in two major forms: (1) video-based e-books (de Jong & Verhallen, 2013; Smeets & Bus, 2012; Unsworth, 2013; Verhallen, Bus & de Jong, 2006); and (2) static visual- based e-books, which readily allow for either simultaneous or sequential presentation of digital content (Verhallen & Bus, 2010). The latter, albeit without video-based content, still has the potential to offer an engaging and stimulating reading environment that effectively enhances reading and vocabulary learning outcomes (Lin, 2014). To facilitate readers’ language development, various explicit reading support cues (eg, glosses, pictographs, color coding, hypertext and QR codes) have been employed in static visual-based e-books to enhance the saliency and comprehensibility of the to-be-learned novel language forms. Nevertheless, these explicit reading support cues may not always facilitate language devel- opment possibly due to a mismatch between how such cues are presented in e-books and how the cues are actually processed by readers (AbuSeileek, 2008, 2011; Liu, 2015). In this vein, AbuSeileek (2008) notes that “how the information is displayed is important . . . because it affects the cognitive aspects of text processing” (p. 262). AbuSeileek further argues that when input display or presentation methods are not considered, explicit reading support cues may not be attended by readers or language learners because of limited attentional resources and their British Journal of Educational Technology (2015) doi:10.1111/bjet.12329 © 2015 British Educational Research Association