Children learn to use gestures through parents and other people who take care of them. It's an important part of language development that requires effort from both parties. It also is a first step to developing language skills. When a child gestures, a parent tends to interperate and verbalize the action or meaning. The verbalization seems to contribute to the child's vocabulary at the agge of 4. Verbalized gestures/meanings are significantly more likely to enter a child's vocabulary months after it is first introduced compared to words spoken by parents in passing.