Have you ever had the experience of talking to someone, and for them to talk to you, only to find that they completely missed the point?
It’s not that you aren’t using a common language, nor that you are not both aware of the topic being discussed: the problem is that the words and phrases mean different things to both of you.
I have this odd circumstance with a work colleague. He will take one word of mine and move it into a context far removed from our current topic. He is not able to listen within the boundaries of our present mutual engagement. In a sense he is violating the rules of conversation, in which we listen to the other person, synthesize the gist and then repeat it back. This is the fundamental way we communicate viz: statement then feedback. Question and response. Suggestion and confirmation.
The process of finding compatible people automatically includes finding those with whom we have this common understanding of language. But it is really more than just language, it is the entire cultural meaning behind the words. And I am not so certain that it’s automatic, in the sense that we’re all too happy to overlook conversational bum notes telling us of linguistic collisions.
Everything is information. If, by noting a certain minor key in conversation we look a little harder at the person, we might avoid someone who will frustrate us in later times. Communication is everything, and talking is a pretty big chunk of everything. It had better be good.