
I was going to ask whether we really and truly know what is a language and what is not. But then I realised that the real issue is that we just can’t agree on a definition that satisfies everyone. Another problem is that we use language to define language, which is circular reasoning, which inevitably leads to self-reflexivity and paradox. For example, I'm using language to explain why you shouldn't use language to explain language.
Most if not all people would agree that dialects, creoles and pidgins are languages. But what about “dead”/archaic languages such as Latin or Cornish?
What about sign language, music, morse code, mime, and mathematics? What about the barking of dogs, the songs of birds and whales and dolphins, the scent trails of ants, the dance of the bees? Computer programming languages? Computer machine code? Which is a language and which is not? Give reasons for your answers.
Language is a tool that helps language-users manage information. Language is a tool that helps language users create, locate, capture, transmit and receive information, as a first step on the road to truth or meaning. It’s the first step because articulating comes before validating; uttering precedes verifying. (And BTW there may not yet be computers that meet the conditions of “personhood”. But there absolutely are computers that are language-users. In fact, all computers are language-users.)