Comparing young second-language (L2) learners in different learning contexts is a valuable, but under-researched, design for determining how L2 experiences impact L2 development. This study addressed this gap by comparing the out-of-school L2 experiences of adolescents (N = 64) learning L2-English as either a community majority language or as a foreign language in an immersion classroom, and examining how differences in L2 experience impacted English receptive vocabulary ability. Participant questionnaires yielded information on sources of L2 input and L2 interaction out-of-school. Results showed the groups were comparable for L2 input, but immersion learners experienced less interactional L2 use and also had significantly smaller L2 vocabularies. Out-of-school L2 experience explained more variance in receptive vocabulary for community-L2 participants, with more significant predictor variables than immersion-L2 participants. L2 interaction variables explained more variance than L2 input variables for both groups, indicating that, overall, interaction is a key source of L2 receptive vocabulary development.