This paper focuses on the Conversation-for-learning pedagogical arrangement (Kasper and Kim 2015), which is set up to maximize the benefit of interaction during the language learning process. The participants to this model have different levels of expertise in their target languages, therefore the talk often displays asymmetries in knowledge and proficiency. The present study examines the generation of learning opportunities in conversation-for-learning approaches, by means of a sequential analysis of how the knowledge asymmetries are brought about and how they are handled by the participants, i.e. by collaborative achievement of definition sequences (Markee 1994). Interaction represents an observable space in which the interactional practices adopted by the participants to gain and maintain intersubjectivity may be observed and appropriated. The present study offers new insights to our comprehension of language learning as a social practice, since it shows that the strategies underpinning and facilitating human sociality are the milestones of the processes that make language-learning happen in interaction.