There are several things you can do to "converse" with your baby. One of the most important is what a lot of people call "baby talk": using that high, lilting voice that many moms (and some dads, too) seem to adopt naturally when talking to their little ones.
Psychologists call this way of speaking "motherese," and they're discovering that the talking style plays a vital role in teaching babies about language. In fact, scientists have documented that the higher and wider pitch, shorter sentences, longer pauses, and repetition are characteristic of motherese in many different languages.
How does this singsong speaking style help babies learn to talk? First, it captures a baby's attention and builds a bond of trust between the two of you by letting him know that you are focused completely on him. Motherese also teaches infants some of the rules of language. For example, experts have noted that the exaggerated intonation and selective word emphasis in motherese makes it easier for a baby to know when it's his turn to "talk." These same traits also help your baby sort individual words from the sea of sounds that he hears.
If your baby is grunting and pointing at something, name what he's focusing on. He'll be thrilled when you name the object of his desire. To a great extent, your baby will learn to speak from you or from her caregiver. She won't get much out of group conversations, in which people tend to speak rapidly and to use unfamiliar words. She also won't learn much from outsiders, whose expressions and tones are alien to her. In fact, third and fourth children often lag behind in language development because they get so little opportunity for one-on-one conversation with their parents—although by the time that they're in preschool, many slow-to-speak kids have caught up with their peers.
Your child has reached the point where he should be able to copy simple demonstrations. This ability to imitate reveals progress in many areas of development, including manual skills, sociability, and intelligence. Taking time to show him how to perform simple tasks will speed his learning and lay the groundwork for future educational experiences.
When your child is in a playful mood, take a basket and some balls and slowly put the balls in the basket, explaining what you are doing while he's watching. Then empty the basket and see if he joins in. If not, don't push—just try again another day.