UnderstandingBy six months old, your baby stops and listens when you say her name, able to distinguish it from other words. She may understand when you say "no." When you talk to her, she makes sounds back at you. If she sees you hide a toy under a rug, she remembers and looks for it there, according to the National Network for Child Care. SymbolsFrom age six to 12 months, your baby loves to explore the world by banging toys together, putting objects in and out of containers and dropping toys on the floor. He appreciates the purpose of objects so uses a brush on his hair, drinks from a cup and offers pretend drinks to dolls and teddies. He recognizes pictures and their symbolic link to the real object. First WordsYour infant plays with sounds in strings, such as, "ba-ba-ba" and "da-da," between six and 12 months. She puts these babbling sounds together in sequences, varying her tone to mimic adult speech. She understands "all gone" and "bye bye," and likes to wave or use simple gestures. She may even use one or two simple words with meaning by the end of her first year. Expert InsightThe U.S. Centers for Disease Control and Prevention notes that your baby's development timeline doesn't exactly mirror that of another child. It recommends contacting your health care provider if, at 12 months or so, your baby doesn't look for objects that he sees you hide; does not wave, shake his head or use other gestures; does not point to objects; and has no single words.