We can understand each other without using words. Using our faces, bodies and tone of voice, we can explain and understand most things. We just need to pay attention and help each other.
We can often see if someone is angry or happy even if they don't speak. We humans use our whole body to speak. And we might not even think about it. But we can also make different gestures to show what we feel. The same gesture can mean different things in different places.