„Those who enter primary school without basic proficiency in the language of instruction, risk falling behind, since language mastery is a precondition for absorbing academic content and interacting with teachers and classmates. PISA data show that, at the age of 15, students with migrant parents who do not speak the language of instruction at home are approximately one year of schooling behind students with native-born parents.“
OECD (Hrsg.), Young People with Migrant Parents (2021), S. 14.