Professor Marc Hauser defines language as an internal process that involves ways of manipulating symbols. It is qualitatively different to "communication."

So the relationship between language and cognition is a tricky one, in part because people have very different views on what language actually is. So, maybe just to be clear, for me, language is a form of internal thought that involves ways of manipulating symbols. So when I create a sentence, what I have functionally done is that I have thought about some aspect of the world that I want to communicate to somebody else and I have got abstract pieces that I can manipulate - like a noun and a verb and an adjective and a determiner. So, language is an internal process that we then externalize by means of communication. And I think it’s important to distinguish between language, on the one hand, and communication, on the other. All organisms have ways of communicating, whether it is by electricity in electric fish, or by song in birds, or grunts and coos in monkeys. We have ways of communicating that are also not language, so I have my body language, we refer to it as "body language", but there it’s a gesture with an arm, or a wink, or whatever it is going to be. Language is a much more formal system, it’s internal, and we need not express it. So, I can have all sorts of thoughts that are linguistic, and I need not express them. So, it is important to keep separate what is described as language, from a linguistic perspective, and communication, which is one way in which we can externalize the internal thoughts.

language, cognition, internal thoughts, body language