The current study was designed to address the important issue of the role of grammar in social interaction and how learners of Spanish as a FL utilize grammatical resources, including increment initiators (e.g., y 'and', pero 'but') and epistemic expressions (e.g., no sé 'I don't know', creo 'I believe', pienso 'I think'). Also, the role of prosody was analyzed as an important resource to convey pragmatic information. The findings highlight the interactive role that increment initiators, elements of epistemic modality, and prosodic cues play during the construction of turn expansion in second language conversations.