If Descartes was because he thought, then he was language because language and thought cannot be separated. Without any doubt, the way we use language defines us, just as Descartes was aware of his consciousness, my use of language defines me: I write, therefore, I am.
There are many ways to use language, but language is the key to any one thing. How people use or abuse language in any given context tells me a lot about their beliefs. For example, if someone is a classically trained violinist who gives a concert, I can reasonably think that she understands music on every possible level. I can say that she probably respects the difficult nuances of a Paganini run. I have no doubt it would take quite a bit of practice and study to learn the music and then play it on her respective instrument. She may even be a bit of a snob about today’s popular music; there’s just not much complexity to what gets radio play these days (though there are exceptions)
Another person may be an expert computer programmer. He knows how to make computers act the way he wants them to act. He probably has no trouble finding work; he might even have little patience for those who can’t do what he does. Others may even treat him the way villagers treated their village priest, with respect that might even rise to awe.
Though there might be many roles through which people relate with me, I relate with the world through the written word wafting across an empty page. For me, as a writer, I see the written word my legacy and as my main place of expression. I appreciate a great line in a song or poem or even a well-crafted article in a magazine. My own writing life has been my center to which I return and has led me back to health.