This study investigates to what degree, and in what manner, the L1 and L2(s) influence spoken French L3. The analysis is divided in two parts. The first examines the cross-linguistic lexemes of 30 Swedish learners, divided into three groups according to previous exposure to French. The results show that proficiency in the L3 is crucial: the least advanced learners produce the highest number of cross-linguistic lexemes, whereas the most advanced learners produce the lowest number. Moreover, the lower the proficiency in the L3, the more background languages are used, and vice versa. Overall, there is a clear dominance of L1 influences. The second part contains six case studies of learners with partly different L1s and L2s. It examines the roles of the L1 and L2(s) in L3 oral production and the decisive factors for these roles. The main result is the use of Swedish L1/L2 and English L1 as instrumental languages, i.e. with clearly communicative purposes, in eliciting and metalinguistic functions. This is due to the interlocutors' common access to these languages. It does not seem to matter if the instrumental language represents a learner's L1 or L2. The fact that there is mutual comprehension seems to outweigh other factors. (Contains 11 notes and 6 tables.)