Which factors coincide with mathematical learning gains in bilingual classrooms?

Although bilingual mathematical learning opportunities have often been requested for multilingual students, little quantitative evidence has been provided that activating two languages has measurable effects on learning gains. This study uses data from a bilingual teaching intervention to investigate which factors coincide most with the mathematical learning gains in conceptual understanding of fractions. Students’ individual and family characteristics have been assessed and participation and language use have been coded in ~95h videotaped teaching-learning processes. A regression analysis shows that students’ learning gains can best be explained by students’ German language proficiency and their use of Turkish and mixed mode, while talking time did not coincide with learning gains. Thus, the connection of languages seems to be even more important for mathematical learning gains than the isolated use of home languages or active participation