This article analyzes, in the context of the sociocultural theory, aspects of the discursive dynamic of a classroom in which writing and orthographic rules were taught. The data were recorded in video and the transcriptions, organized in teaching episodes, were submitted to microgenetic analysis. From the analysis it can be inferred that the teacher discourse is heterogeneous since it lets the students participate in the process of enunciation and, at the same time, controls the production of univocal meanings related to the orthographic rules. The data also indicate that students internalize not only the teaching contents but also more general aspects of the school discourse, as disciplinary rules and metacognitive strategies of learning.
