This study investigates how previous exposure to a foreign language and culture influences student performance in online knowledge-building tasks. As knowledge-building tasks allow students to share and distribute their knowledge; this study examines whether foreign language and culture knowledge is also distributed amongst the group. The study was conducted in the Catalan region of Spain where the participating grade nine students were learning English as a foreign language and they were all bilingual speakers of Catalan and Spanish. The students were assessed to determine their previous exposure to the English language and culture, and they were divided into low-, medium-, and high-levels of English language exposure. The students wrote both a pre-test and a post-test before and after the study, and a one-way ANOVA was used to determine whether exposure to English influenced the performances on the tests. The analysis shows that the student scores increased at the same rate across the groups. This indicates that the students did not share their knowledge of the English language and culture with their peers in this online writing task; however, the students generally showed an increase in their comprehension and production of the foreign language. A further analysis of the posts in the forum indicates there were issues with pragmatic variability, which was likely due to the absence of participating native speakers of English.