By the age of three, children in literacy-rich households will hear some 20 million more words than their less-advantaged peers …

„Researchers in the US have estimated that by the age of three, children in literacy-rich households will hear some 20 million more words than their less-advantaged peers. In the United Kingdom, three-year-old children of highly educated parents have vocabularies that are nearly a year ahead of children whose parents have no qualifications.“

EU-Kommission (Hrsg.), „EU High Level Group of Experts on Literacy. Final Report“