Why it’s important: It was once believed that kids learned language merely by overhearing lots of it, says Jennifer Lansford, Ph.D., a research professor at the Sanford School of Public Policy at Duke University and an editor of Developmental Psychology. This study is part of a body of evidence suggesting that good old conversation with your kid is what’s most important. “Starting from infancy, children learn grammar, vocabulary, and comprehension better when you talk with them than if they are just passively listening,” says Dr. Lansford. The most enriching conversations follow a child’s lead. For instance, if your toddler says, “Car!” reply in ways that build on that: “Yes, that is a red car. Do you see a blue car?”