Fostering German-language learners’ constructions of meanings for fractions—design and effects of a language- and mathematics-integrated intervention

Learning situations that concentrate on conceptual understanding are particularly challenging for learners with limited proficiency in the language of instruction. This article presents an intervention on fractions for Grade 7 in which linguistic challenges and conceptual mathematical challenges were treated in an integrated way. The quantitative evaluation in a pre-test post-test control-group design shows high effect sizes for the growth of conceptual understanding of fractions. The qualitative in-depth analysis of the initiated learning processes contributes to understanding the complex interplay between the construction of meaning and activating linguistic means in school and technical registers.