Children today are exposed to technology at a very young age, with educational media becoming increasingly salient in the lives of young children. Many programs are designed to equip preschool-aged Dual Language Learners (DLLs)–children who are exposed to two languages in early childhood–with English vocabulary knowledge to prepare them for school, but the specific on-screen mechanisms that facilitate vocabulary learning for DLLs have yet to be examined. This dissertation is comprised of three papers that collectively investigate the instructional supports on screen and in the media viewing context that influence L1 and L2 vocabulary knowledge in DLLs. The theoretical assumption underpinning multimedia learning in this dissertation is dual-coding theory (Paivio, 1986, 2008), which asserts that information is more fully processed when it is transmitted through verbal (speech) and nonverbal (imagery) systems. The interconnections between these systems create coherent mental images that serve as essential scaffolds for word learning among young DLLs.

The overarching goal of this dissertation is to understand how educational media can be optimized for the early bilingual development of DLLs. I approach this from three different perspectives, using a within-subjects design and experimental methods to investigate how (1) specific screen-based pedagogical supports, (2) instructional contexts used on screen, and (3) the language of instruction might influence L1 and L2 vocabulary learning among DLLs. Findings from all studies indicate that children were able to learn both L1 and L2 vocabulary words from screens. In addition, the repetition screen-based pedagogical support, participatory and expository instructional contexts, as well as the language of instruction significantly influenced vocabulary learning among DLLs. Moreover, children with varying levels of L1 and L2 proficiency benefited from certain supports more than others, stressing the importance of treating DLLs as a heterogeneous group. In an age where “screen time” is in the everyday discourse of families, educators, health care providers, and policymakers, this dissertation addresses a timely question of what “quality” screen time might look like, and how it can be strategically used to promote L2 development and heritage language maintenance for linguistically diverse populations.