The last two decades have seen an increasing interest in what characterizes the left and right sentence peripheries. This paper is the partial account of a research project at Stockholm University which aims at comparing highly proficient Swedish users of L2 French and Spanish with native speakers with regard to how they structure the syntactic peripheries in natural colloquial speech. In the present context, however, only Spanish and Swedish will be accounted for. The analysis contains two aspects: on the one hand, a typological study comparing native speakers of the two languages and, on the other hand, a study addressing the question of the upper limits of L2 acquisition while comparing Spanish L1 and L2 speakers, the latter having Swedish as their L1.Results addressing the first aspect show that native speakers of Spanish put more weight on the left periphery than do native speakers of Swedish, who, in turn, put considerably more weight on the right periphery, thus showing a clear typological difference. As regards the second, acquisitional aspect, the behaviour of the high-proficient L2 speakers closely resembles that of the native speakers, with only a few albeit interesting exceptions. On the other hand, no clear instances of L1 transfer can be observed in the Spanish L2 productions.