摘要：Abstract This study aimed to investigate the proportion of L1 and L2 use while writing in L2 and also the way the language use is related to conceptual and linguistic activities. Furthermore, it focused on the effects of the language use and conceptual and linguistic activities on L2 text quality. To carry out the research, twelve Iranian L2 (English) learners were instructed to write an argumentative composition under think aloud condition. The results indicated that L1 is used quite frequently and predominantly for performing conceptual activities rather than linguistic ones. It was also concluded that L1 use and conceptual activities contribute to the better text quality.
