Practical instructional approaches are often criticized for focusing too exclusively on vocabulary work whereas research has revealed rich insights into the role of language on the discursive level. On the other hand, the mathematics education research community focusing on language has not yet filled the gap between research and classroom practices. In this paper, we present the theoretical frameworks which have grounded our attempts to fill this gap through topic-specific design research on fostering the competence of language learners. The frameworks are used for comparing two teaching–learning arrangements based on a macro-scaffolding and a relating registers approach, one focusing on discursive activation, the second with additional, integrated lexical support. The paper shows how the theoretical frameworks become visible in the design of the intended curriculum and the realized curriculum shaped by teachers’ micro-scaffolding moves.
