Literacy experts have previously documented a connection between a child’s early vocabulary and later success in reading comprehension. In a study tracking children from age 3 through middle school, David Dickinson, now a professor of education at Vanderbilt University, and Catherine Snow, an education professor at Harvard University, found that a child’s score on a vocabulary test in kindergarten could predict reading comprehension scores in later grades.
Mr. Dickinson said he feared that some preschool teachers or parents might extract the message about the importance of vocabulary and pervert it. “The worst thing that could come out of all this interest in vocabulary,” he said, “is flash cards with pictures making kids memorize a thousand words.”
Instead, literacy experts emphasize the importance of natural conversations with children, asking questions while reading books, and helping children identify words during playtime.
Nearly two decades ago, a landmark study found that by age 3, the children of wealthier professionals have heard words millions more times than those of less educated parents, giving them a distinct advantage in school and suggesting the need for increased investment in prekindergarten programs.
Now a follow-up study has found a language gap as early as 18 months, heightening the policy debate.
The new research by Anne Fernald, a psychologist at Stanford University, which was published in Developmental Science this year, showed that at 18 months children from wealthier homes could identify pictures of simple words they knew — “dog” or “ball” — much faster than children from low-income families. By age 2, the study found, affluent children had learned 30 percent more words in the intervening months than the children from low-income homes.
The new findings, although based on a small sample, reinforced the earlier research showing that because professional parents speak so much more to their children, the children hear 30 million more words by age 3 than children from low-income households, early literacy experts, preschool directors and pediatricians said. In the new study, the children of affluent households came from communities where the median income per capita was $69,000; the low-income children came from communities with a median income per capita of $23,900.
Since oral language and vocabulary are so connected to reading comprehension, the most disadvantaged children face increased challenges once they enter school and start learning to read.
“That gap just gets bigger and bigger,” said Kris Perry, executive director of the First Five Years Fund, an advocate of early education for low-income children. “That gap is very real and very hard to undo.”