This special issue presents results from comparative research into the principles constraining learner varieties (interlanguages) in use. The contributors analyze the oral production of complex verbal tasks (descriptions, instructions, narratives, retellings) in L2 Dutch, English, French, German, and Italian, concentrating on the way information from different semantic domains is organized across utterances (referential movement) and on a major aspect of the interaction between utterance-level and discourse-level constraints, namely, scope phenomena. We hope the results presented here will provide insights into the structural and communicative factors pushing, or hampering, L2 acquisition and will further our understanding of how the organizing principles interact at different levels of discourse production, be it in L1 or L2.