Language is any means of communication among a group. If my throat meat vibrates, and a thought comes in your brain, and that's the thought I wanted in your brain, then that is communication. If a group of people share a communication, that's a dialect. A group of dialects where you can understand most of it between each other is called language.
And at no point does the language dictate what communication is, It's the other way around.
Ugh ..
*Reluctantly changes down vote to up vote-