Is it a defining aspect of culture, or simply a form of communication between beings?
The obvious answer to the question is that language is a little of both. Over the past few years however I have begun to question what the future of language will be and I can't help but feel that over time, different languages will cease to exist.
Lets think about this logically: If I didn't know anything about human culture or the development of language, I would probably assume that every person on the planet would use the same sounds to communicate, we are the same species after all. Furthermore, if I was raised in an area where I spoke a language that was different than the common language, I would probably want to adopt the common form of sounds so that I could actually interact with others. This has already started happening all over the planet. In Indonesia upper class and upper middle class families have begun teaching their children only English, so they have a leg up on the rest of the students. The government is worried that their language will be lost in only a few generations and with it their culture (at least of some level). For some this is horrible, but for others like me, I welcome the day when I can travel anywhere in the world and know that I will be able to communicate with the people.
On that note I find it naive to think that once language is gone, a culture loses its roots. Language is simply a tool, like tools of the past it leaves its mark on all that it built. Humans will always remember the days of varied language and I'm sure in a few hundred years it will be a point of some laughter that many fought against a standardized form of communication.
So what is The Language? Well to be honest it is probably going to start with English. Now I say start with because in reality there will be varied dialects for tens if not hundreds of years, making some English seem like another language (have you ever heard someone speak with a thick Irish brogue?). Over time things will settle out and with the spread of technology and communication a world language will be established, it has to be.