Ask just about anybody "what is language?", and there's a pretty good chance you'll get an answer that says something about communication and/or information.
Communication (in general) doesn't quite work. One of those strange ones, where the norm is so at odds with the theory. The ideal information or communication schema says that you have a sender, say somebody talking to you, and a receiver - you. Between you passes a message, via the communication 'channel', whatever it happens to be. Sometimes you get interference in the message, via some sort of noise in the channel. So a car may be going by when the person is talking, and you miss part of what they say.
Information scientists building networks invented this schema, and it really shows. Because in the real world it's pretty obvious that the sender and receiver hardly ever get the same meaning in an act of communication. Not because people always misunderstand one another, often they don't, but even when you feel you're communicating well, meaning is always in the hands of the receiver. You can say whatever you like, as clearly as you can, and out of 10 people who might be listening you'll get at least 3 different interpretations of what you meant. All writers and speakers know this. The norm isn't transmission of some static message, that's an ideal that is never achieved. Noise is the baseline, not communication.
And again not because noise interferes with a pure message, but because there is no such thing as a pure message. Communication is an act, an event, it isn't a transmission. Network engineers,who invented much of the modern theory of communication, adopted even by the social sciences and everyday chat, no doubt took the final outcome of bits and bytes transmitting correctly as the baseline. But even there anybody who sets up networks knows that you need all sorts of error correction and standardisation and redundancy and other fancy magic to get even close to something that looks like a message transmitted from point A to point B.
The same applies for language. We all talk to each other, every day. But are we passing 'messages' back and forth? Or does each statement accomplish an act, within the statement itself? This is a bit clearer if you look at certain linguistic categories of statement, such as the performative. In performative speech you accomplish an act in speaking - for example you swear to something as you say "I swear". There is no distinction between action and speech - speech is itself an action. Or giving a command by using the imperative, or making a promise, or asking somebody to do something. All acts.
Language is always self-referential. It doesn't refer to something else, it refers to itself. It doesn't go from something seen to something said, it always goes from something said to something else said. From one act to the next linked act. No matter how trivial the chit chat, it's accomplishing an act of some kind. If I walk into work and say "good morning" to people it's not me exchanging information- "it's morning and it's a good morning" - it's me undertaking an act of maintaining a certain set of relationships with them, which have little to do with it being morning at all. If I sit and talk about something I watched on TV last night, I'm not trying to convey information about what was on TV, I'm engaged in an act with a whole range of motivations and histories relating to why that show interested me, why I want to share it with that particular person or people, etc.
Not much of this is conscious. We use language all the time to accomplish acts, without thinking about it. It's only when we step back and theorise about it that we strip away the essentially pragmatic nature of language and turn it into some sort of broadband network. But it's always about acts - there isn't language used just for idle chat and then language used for action. It's always action, and the action is immanent to the speech. The speech is the action.