I found it incredible that the baby in this video is able to use hand gestures in a coherent way. Additionally, the baby shows signs of understanding the structure of conversation. He pauses and responds at appropriate times.
In the podcast Hidden Brain, they reference this viral video of two babies babbling (Vedantam, 2019). Take a moment to watch their body language. They have decided to adhere to unspoken rules of conversation. Let's consider some nonverbal features of dialogue evident in this video:
taking turns to talk
mimicking one another's actions
laughing
facial expressions
Yet another example of the power in nonverbal communication. The babies here are responding to music, which is likely activating the right hemisphere of their brains. Just like the video above, they acknowledge certain characteristics of conversation without speaking.