Just because your baby sees you using signs doesn’t mean she has yet developed the skills and knowledge necessary to do them herself. Think about what babies need before they can spontaneously point at a dog and produce the dog sign.
As mentioned previously, they need to have seen you do the sign often enough to understand the equivalence between the sign and the object.
They also need to be able to imitate the movements involved. Finally, they have to have the memory capacity to recall all these things the moment they see the dog and decide it’s important enough to tell you about. Each of these is an important piece of the language puzzle.
One wouldn’t expect a three-month-old, for example, to fit all these components together. But by the time they are nine to twelve months old, most babies can. One clear indication that your baby is ready to start using signs himself is
the milestone of learning to wave bye-bye. Parents almost instinctively teach their children this sign, saying the words and waving their hands. Most don’t think of this as a sign, but it really is. It’s a simple sign that stands for a concept—somebody or something leaving. Similarly, if your baby is shaking his head for no and
nodding for yes, he’s definitely ready to start signing.