Interesting data on the number of words babies hear every day, by economic class:

Class divisions are hardening in America, and the reasons may go deeper than the economic. Earlier in April, the New York Timesreported on the lifelong effects of the simple act of talking to your baby. One of the most important changes of our time has been the trend since about 1980 of upper-class families to invest more time in their children even as lower-class families have invested less.

Children whose families were on welfare heard about 600 words per hour. Working-class children heard 1,200 words per hour, and children from professional families heard 2,100 words. By age 3, a poor child would have heard 30 million fewer words in his home environment than a child from a professional family. And the disparity mattered: the greater the number of words children heard from their parents or caregivers before they were 3, the higher their IQ and the better they did in school. TV talk not only didn’t help, it was detrimental.

So there you have it. Talk talk talk!