Ming @ Agents of Speech explains why gestures matter for speech development. Kids who point, beckon, or use hand movements with words are on track. Few gestures can signal a delay worth discussing with a speech therapist.
Talking about imitation. If they rely on you for doing a lot of direct modeling and prompting for imitation, then that means that they cannot really do it themselves. When we talk about imitation, we will think about gestures. So gestures are very important in language development. If your child uses very few communicative gestures, like pointing, like come over, or like tapping themselves, tapping you, and they use less supplementary gestures, which means adding some meaning to a word. Maybe they say water, and it's like hot. That means hot water. Okay, so there's some supplementary gestures that a child might use to add to their limited vocab and try to tell you more about what they're trying to say. Then that's a good thing. If you see they don't really use that, then it's also a risk factor that you need to take into account. And these things you can actually tell your speech therapist about so that they have a much bigger and clearer picture. The most important is that you're able to remember these things and tell the speech therapist what's going on.
