„Students of Turkish origin appear to be particularly disadvantaged. One reason for this disadvantage could be that despite having grown up in Germany, a large proportion of ethnic minority students use a minority language in their everyday communication with parents and, to a lesser extent, with friends and classmates.“
Julian Seuring u. a., Ethnic Classroom Composition and Minority Language Use among Classmates: Do Peers Matter for Students’ Language Achievement? In: European Sociological Review, 2020, Vol. 36, No. 6, S. 922.