The overriding philosophy of The Alchemist could be described as a kind of pantheism, the belief that everything in the universe is God. Coelho introduces us to the notion that we are all part of the Soul of the World, a soul that links us all together: man and beast, sun and sky, rocks, plants, and trees. The Soul, as it comprises every living thing, is itself a living force. What's more, it has its own language, "the language of the world."

The language of the world speaks to each and every one of us, even if we don't always hear it. Although there are many different languages in the world, underlying them is one universal language that speaks to our common humanity. It is a language of enthusiasm, a language that encourages people to do good things, to follow their life goals.

Even those unwilling to follow their Personal Legends, like the crystal merchant, understand the language of the world and what it means. The merchant knows that Santiago is listening to the world language in coming up with all kinds of good ideas for drumming up trade.

Santiago realizes that desires ultimately originate in the soul of the universe; if you want anything in life, it's because the universe as a whole wants it for you. And that desire is communicated through the language of the world, which has the power to guide us along the path of life, if only we'd stop and listen to it.

In Coelho's The Alchemist, the language of the world is the way all things communicate because all things are one. Santiago tries to tell the Englishman this. In his turn, the Englishman tells Santiago that all he needs is found in books; but the Englishman finds nothing important in trying to listen to the desert or by searching for omens. Likewise, Santiago learns nothing from the Englishman's books. However, Santiago does not dismiss the Englishman's way of learning: he only knows that he cannot learn to communicate with the world in that way—

"Everyone has his or her own way of learning things," he said to himself. "[The Englishman's] way isn’t the same as mine, nor mine as his. But we’re both in search of our Personal Legends, and I respect him for that."

So both men continue on their quest to discover their Personal Legend. The more Santiago looks, the easier it becomes to recognize omens. He develops a kinship with nature and can read the signs it shares with one who is observant.

The language of the world manifests itself in several ways. During the account of the boy's journey, we find that he understands the language of the world based on one's response to the world:

There was a language in the world that everyone understood…It was the language of enthusiasm, of things accomplished with love and purpose, and as part of a search for something believed in and desired.

In the desert, the alchemist describes the relationship Santiago must develop with nature, and in so doing, understand the language of the world:

You don’t even have to understand the desert: all you have to do is contemplate a simple grain of sand, and you will see in it all the marvels of creation…Listen to your heart.  It knows all things, because it came from the Soul of the World...

So the heart knows the language of the world. It is also found in nature. 

The chief of a military camp takes the alchemist and Santiago captive. The only way the boy can escape death is to prove that he has great power—a power of which Santiago knows nothing. However, in the spirit of sink or swim, Santiago speaks with the wind, the sun and the desert; and finally he communicates (without words) with the Soul of the World (the Hand That Wrote All)—listening with his heart. It is in these discussions that Santiago learns how to move himself with the wind's help.

The language of the world is also present in the instantaneous understanding that Santiago and Fatima have:

It was the pure Language of the World...What the boy felt at that moment was that he was in the presence of the only woman in his life, and that, with no need for words, she recognized the same thing.

Because we are all connected, we are not only made of the same stuff, but we can also communicate with nature if, as Santiago tells the Englishman, we listen to nature speaking to us. In this regard, we should also, then, be able to speak to one another regardless of where we come from, which Santiago discovers in being able to understand people who do not speak his native language.

The language of the world refers to the oneness of all things: that everything in the universe is tied together. And believers of this truth feel that the language of the universe links people to the world and to each other.