The number of words we say to our children matters:

[…] two researchers, Todd Risley and Betty Hart, studied the effects of how parents talk to a child during the first two and a half years of life. After meticulously observing and recording all of the interactions between parent and child, they noticed that on average, parents speak 1,500 words per hour to their infant children. “Talkative” (often college-educated) parents spoke 2,100 words to their child, on average. By contrast, parents from less verbal (and often less-educated) backgrounds spoke only 600 per hour, on average. If you add that up over the first thirty months, the child of “talkative” parents heard an estimated 48 million words spoken, compared to the disadvantaged child, who heard only 13 million. The most important time for the children to hear the words, the research suggests, is the first year of life.

Risley and Hart’s research followed the children they studied as they progressed through school. The number of words spoken to a child had a strong correlation between the number of words that they heard in their first thirty months and their performance on vocabulary and reading comprehension tests as they got older.

The kind of things we say to our children also matter.

[…] the way a parent spoke to a child had a significant effect. The researchers observed two different types of conversations between parents and infants. One type they dubbed “business language”—such as, “Time for a nap,” “Let’s go for a ride,” and “Finish your milk.” Such conversations were simple and direct, not rich and complex. Risley and Hart concluded that these types of conversations had limited effect on cognitive development.

Here’s the ideal way to talk to our children:

In contrast, when parents engaged in face-to-face conversation with the child—speaking in fully adult, sophisticated language as if the child could be part of a chatty, grown-up conversation—the impact on cognitive development was enormous. These richer interactions they called “language dancing.” Language dancing is being chatty, thinking aloud, and commenting on what the child is doing and what the parent is doing or planning to do. “Do you want to wear the blue shirt or the red shirt today?” “Do you think it will rain today?” “Do you remember the time I put your bottle in the oven by mistake?” and so on. Language dancing involves talking to the child about “what if,” and “do you remember,” and “wouldn’t it be nice if”—questions that invite the child to think deeply about what is happening around him. And it has a profound effect long before a parent might actually expect a child to understand what is being asked.

In short, when a parent engages in extra talk, many, many more of the synaptic pathways in the child’s brain are exercised and refined. Synapses are the junctions in the brain where a signal is transmitted from one nerve cell to another. In simple terms, the more pathways that are created between synapses in the brain, the more efficiently connections are formed. This makes the subsequent patterns of thought easier and faster.

Synapses are exponential:

This matters. A child who has heard 48 million words in the first three years won’t just have 3.7 times as many well-lubricated connections in its brain as a child who has heard only 13 million words. The effect on brain cells is exponential. Each brain cell can be connected to hundreds of other cells by as many as ten thousand synapses. That means children who have been exposed to extra talk have an almost incalculable cognitive advantage.

Finally, cognitive advantage might be more important than parents’s income, ethnicity, or education, in determining the children’s future:

What’s more, Risley and Hart’s research suggests that “language dancing” is the key to this cognitive advantage—not income, ethnicity, or parents’ education. “In other words,” summarized Risley and Hart, “some working-poor people talked a lot to their kids and their kids did really well. Some affluent businesspeople talked very little to their kids and their kids did very poorly…. All the variation in outcomes was taken up by the amount of talking, in the family, to the babies before age three.” A child who enters school with a strong vocabulary and strong cognitive abilities is likely to do well in school early on and continues to do well in the longer term.

This is from “How Will You Measure Your Life“, by Clayton Christensen, James Allworth, and Karen Dillon (emphasis mine). I’ll have to re-think how I talk to my child from now on.

The best appreciation I can give to a book is to feel the need to own a physical copy of it. This book belongs to that criteria. Highly recommended.