Educational Research in Multilingualism indicates that multlingual students' thinking-and-speaking processes might be associated with different nuances when interpreting concepts and notions. From a subject-didactical perspective, this leads to the question, if or how these nuances can be reconstructed and which possible relevance they possess for mathematical learning trajectories. In a design-based study from the German context, the activation of multilingual resources in the conceptual development of German-Turkish 6th grade learners is examined. Follwing the translanguaging-paradigm, the learners were allowed to use all of their linguistic resources in a small-group-setting with a mulilingual learning environment for conceptually understanding fractions (with the share-notion being focussed), being designed according to a content-and-language-integrated approach. This article outlines the synthesis of the interdisciplinary theoretical background as well as the main research outcomes regarding the form and function of multilinguals' learning trajectories by reconstructing conceptual fields and further analysing these with the linguistic translanguaging-paradigm in an interdisciplinary approach.
