The paper presents a case study of the mathematics enculturation of a Grade 5 learner, (Sarah), at a school in Limpopo Province of South Africa. The case study sought to explore the attributes of mathematics enculturation in social interaction as a process of learning. A qualitative approach was adopted in collecting and analysing data. Data were constructed by capturing critical incidents and keeping a chronological account in a researcher journal of the discussion observed in Sarah's group during lessons. Qualitative data from Sarah's group, working together on activities, reveal the following constructs as key to understanding mathematics enculturation in the classroom: language, shaping of learners' ideas, and negotiation of meaning. The implication is that oral communication, which includes feedback, plays a major role in making social encounters into learning events that facilitate sense-making and understanding.