Deutschland: „The descriptive information on vocabulary for each SES group (Anm.: SES = socioeconomic status) reveals that children whose mothers have a low or no secondary education lag behind other children at age five and fall even further behind over time.“
Univ.-Prof. Dr. Thorsten Schneider u. a., Development of socio-economic gaps in children’s language skills in Germany. In: Longitudinal and Life Course Studies, vol 13, no 1, 2022, S. 100.