Classroom interaction has been widely studied using the conversation analysis methodology in order to explore and understand interactional practices that enhance language learning. This research has been traditionally focused on the canonical teacher-student classroom interaction, called Initiation-Response-Feedback (IRF) sequence, composed by a teacher's first turn, a student's response and a third turn performed by the teacher to evaluate or give feedback. Variability within the IRF sequence, regarding the learner's initiative to take the floor, has been investigated and its potential benefits to generate language learning opportunities have been acknowledged. Employing Conversation Analysis, in this article we investigate learner initiatives in teacher-student interactions obtained from 40 hours of video-recorded Spanish as a foreign language lessons in Barcelona, Spain. We aim to explore and characterize students´ initiatives in a meaning-focused round robin sequence and analyze the implications of nonallocated turns for the progressivity of the interaction. The analyses reveal that some initiatives do not alter -but support-the ongoing interaction, while others lead to marked changes and readjustments in the IRF sequence.