Parental education has been shown to be a stronger predictor of gaps in early language development than family income …

„Parental education is typically used as a proxy to capture differences in the family social environment, and has been shown to be a stronger predictor of gaps in early language development than family income, as well as an important factor for explaining gaps in early primary school achievements.“
OECD (Hrsg.), The economic costs of childhood socioeconomic disadvantage in European OECD countries (2022), S. 13.