2000 words per hour?

This article states that some "professional" parents speak 2000 or so words per hour to their child on average, and the number of words spoken to a child has an effect on achievement. To me, 2000 words per hour seems like it would be nearly constant chatter, but maybe it is true that many parents speak this much to their children. I have no idea how many words per hour I speak to my son, but I am not constantly talking to him. Maybe I will talk more when he makes more of an initiative to talk to me!