Poetry is often regarded as a mystery, and in some respects it is one. No one is quite sure where poetry comes from, no one is quite sure exactly what it is, and no one knows, really, how anyone is able to write it.
The Greeks thought, or at least said, that it came from the Muse, but in our time no one has been able to find her. The unconscious has been offered as a substitute, but that, too, is hard to locate. How anyone is able to write it is explained in this way: the poet is a genius who receives inspiration.
One way to get a little more clarity on the subject was suggested to me by a remark of Paul Valéry’s. Thinking about what could be expressed in poetry but not elsewhere, he said that poetry was a separate language or, more specifically, a “language within a language.”
— Read on www.nybooks.com/articles/1998/05/14/the-language-of-poetry/