Research on the acquisition of Portuguese by Spanish speakers has traditionally minimized the relevance of the sociohistorical conditions in which language development occurs. Consequently, linguistic production has been described as a univocal object of analysis dissociated from contextual features and from the influence of the interaction which characterizes the production. This paper is a case study that discusses the extent to which a learner's voice varies in three different settings and how these settings influence and/or constrain the occurrence of this polyphony. Central to the authors' argument are the complexities involved in oral practices.