Extramural exposure, through activities such as watching TV, gaming, networking, and online reading, has become an important source of vocabulary acquisition in English as a foreign language, particularly when learners' first language (L1) has many cognates with English. Our study examined extramural vocabulary acquisition of 10th-grade L1 speakers of noncognate languages over one school year and explored the effects of digital activities and initial lexical knowledge of the participants on their vocabulary gains. Learners reported the amount of digital activity, took a vocabulary pretest, and kept vocabulary diaries where they recorded, on a weekly basis, the new words they encountered. At the end of the study, each student took a personalized test that included all the words recorded in their personal diary. The results indicate that (a) all learners gained some out-of-school word knowledge, (b) students with better initial vocabulary knowledge gained more words, and (c) the initial knowledge contributed to out-of-school learning more than the amount of digital activity.