Your baby learns language by listening to you and others use it. Though your baby certainly doesn't understand everything you say, she no doubt picks up glimmers of meaning here and there. Especially if you speak to your baby a lot, she will understand dozens of words before she utters anything recognizable.
One of the first words your baby will probably understand is the word no. By around six months, your baby will begin to associate a sharp "No!" with the idea that she has to stop doing whatever she's doing. By nine months, she may understand a few simple phrases that are often directed toward her, such as "Wave bye-bye," or "Drink your bottle."
If you want to check your child's understanding of words, even before she speaks, try these two games:
- Ask your baby to find a favorite object. "Where's your blanket?" "Where's your teddy bear?" If she turns toward it, your baby probably knows what blanket or teddy bear means. This game works even better with your baby's favorite people. If you have several visitors for your baby to choose from, have your partner hold the baby and ask, "Where's Mama?" or "Where's Daddy?" If she turns toward you, you're golden.
- See whether your baby can do what you ask if you make simple requests. Some examples include, "Wave bye-bye," "Sit down," "Give me a hug," "Throw the ball," "Drink your juice," or "Fetch my slippers." See how many your baby understands.
If your baby does what you've asked her to do, let her know how pleased you are. If she doesn't, then ask her to do something else or drop the game for a while. (Of course, just because your child refuses to do what you've asked doesn't necessarily mean that she has failed to understand you. She may just be loathe to perform on command like a trained seal.)