Imagine you're playing a game where you don't use words, but you communicate by being quiet. In a way, that's like what this quote is saying. Sometimes, not saying anything can still send a message, just like when you use words.
Think about a picture that doesn't have any words, but you still understand what's happening. Silence can be like that too. It's a way of saying something without using your voice.
Imagine you're with a friend, and they look sad. You don't have to ask them what's wrong; their face tells you. This quote means that even when we're not talking, people can understand how we feel or what we mean, just by how we act or look.