A substantial percentage of the kindergarten population in the Netherlands lags so far behind in L2 proficiency that they may hardly profit from picture storybook reading promoted as a remedy for vocabulary deficits. The first aim of this study was to test whether young children with limited proficiency in their second language benefit more from repeated readings of a digitized storybook that includes video instead of merely static illustrations. Subjects (N = 106) were randomly assigned to a control condition or one of four treatment conditions crossing two levels of repetition (one or four exposures) with two versions of the same story (merely static pictures vs., instead of pictures, video representations). A second aim was to test the hypothesis that video storybooks promote the acquisition of new language because children are more inclined to sustain their efforts to extract meaning from the text when video is added. As indicator of the amount of mental effort, skin conductance was monitored in a sub-group that encountered the same story four times (N = 42). The results support the hypothesis that video storybooks offer a suitable framework for vocabulary acquisition in kindergarten children with low L2 proficiency. Furthermore, mental effort remains at a higher level when a video storybook is repeated and this stability is one of the generating mechanisms through which video storybooks are more effective than static storybooks at stimulating L2 vocabulary.

Keywords
storybook reading, video storybooks, vocabulary, mental effort, repeated readings, psychophysiology, children at-risk, L2 proficiency