Kids from professionals' families have heard 30 million more words from adults by the time they get to school than kids from poor families.
This is a gap that families of any class can close.
One of the saddest footnotes I know is early on in Annette Lareau's Unequal Childhoods. She writes that by the age of three, middle class kids have a bigger vocabulary than welfare parents do. So the poor parents will have to work on their own language skills to help their kids.
They should. Win-win.