I know animals often imitate specific behaviour (like when they show their teeth to evoke "danger!" in the reciever) as a form of communication. Although, for a fully-fledged language where we can express anything we can think of to develop, we need more complicated signals.
And for that, we need both the reciever and the signaler to understand the same signalling system. And since for a language as complex, the animals need to share a lot of similar "associations" with similar signals - it's good when the communicating animals orientate a similar environment - such as siblings.
Is this a possible explanation of the evolution of language?
I know the signalling theory is a biological branch on its own, however I seem not to be able to come up with an alternative explanation. Also, I know that this kind of group selection is sometimes used to explain the evolution of altruism. So is this how the evolution of communication happens?