Wikis represent a particular type of collaborative learning environment where collaboration can result in aggregated, collective products. This study makes the claim that such potential challenges language production practices in school where the individual learner's output is often the focus of attention. The argument is put forth by juxtaposing theory, literature review, and videotaped wiki activities. Wikis are examined in a sociocultural perspective, in particular the notions of collective zones of proximal development and sociogenesis – that we come to knowledge by taking part in activities where individuals relate to a greater collective that evolves over time and where language and material artifacts function as structural resources. A review of some recent research in CALL and Second Language Acquisition (SLA) seeks to form a backdrop for this study of collective language production. Empirically the argument is illustrated and supported by selected videotape transcripts of learner interactions involving the use of a wiki in an English as a Foreign Language (EFL) classroom. The study shows that learners work in and across activity types that create tensions between individual and collective, institutional and novel practices, but that the wiki also holds the potential for collective knowledge advancement and language development.