Serve and return
A baby babbles, points, makes a face, reaches. That is the serve. An adult who notices and responds in kind — names the thing, babbles back, follows the child's gaze — returns it. Repeated thousands of times, these exchanges are a large part of how early language and social circuitry gets built. The practical version is unglamorous: notice what the child is already looking at, name it, wait for them to respond, and follow their lead instead of redirecting to what you wanted to teach.
How strong is this: Well established in developmental science and summarized for the public by Harvard's Center on the Developing Child. check it: Center on the Developing Child, Harvard University
