Surveys on linguistic and biographical data collection in a multilingual society have been used both nationally and internationally for decades to gain an overview of home languages spoken in different private and public domains. In this article, obtaining the data via a questionnaire, linguistic and biographical data of students are analysed descriptively as part of the BMBF-funded research project “SchriFT”. The German- Turkish language use is considered in more detail. We analyse not only the distribution of home languages, but also the language acquisition type and the use of languages in the context of family and peer group communication. To investigate this, we focus our descriptive analysis on German and Turkish-speaking pupils in the 7th and 8th grade at schools in the Ruhr area of Germany (n = 134) to describe main features. The results show the intergenerational dynamics of multilingual pupils‘ functional language use, highlighting the specific role of grandparents for the transmission of the Turkish language.