Thirty million is a big number, it’s a lot of money, a lot of people, a lot of anything. Imagine it in terms of a child’s vocabulary. Imagine if your child heard thirty million fewer words by the age of three than the child sitting next to her in school. Imagine how that would affect her vocabulary.
Research shows that up to 98% of words used by a three-year-old are directly derived from their parents’ vocabulary. They also found that the number of words the children learned varied greatly among socio-economic lines, with children from professional families hearing approximately 30 million fewer words over a child’s first three years.