After the advent of socio-cultural theory of learning and the widespread applications of its tenets in second language pedagogy, learners’ first language was praised to play certain facilitative roles in second language learning. The functions of L1 use have also been explored in collaborative writing tasks, but the focus has long been on the similarities of writing processes in the two languages and the transfer of strategies from the first to the second languages. However, one basic difference between first language and second language learners, which seems to have been overlooked, is the fact that second language learners have two languages at their disposal, and hence may benefit from them both. The present study was hence designed to investigate first language collaborations of learners engaged in a second language writing task by collecting audio and written data from 36 (12 groups of 3) Persian speaking intermediate English learners while writing an argumentative paragraph. 6 of the 12 groups were asked to collaborate in their first language and the others were limited to using the second language in their collaborations. The results of comparisons between the first language and second language groups indicated that while the former groups focused on task management, task clarification and grammar, the latter groups were more concerned with vocabulary and content
