Foundations of xenocryptography:

If we find signals that obey Zipf’s Law, for example, that would encourage us to go ahead and look for syntax-like structure within the signals in order to quantify how complex the candidate message actually is. […] To transmit knowledge, even a very advanced extraterrestrial civilization would still have to obey the rules of information theory. While perhaps not being able to decipher such a message because of lack of common symbols (the same problem we have with, for example, humpback whales), we would get an indication of how complex their communication system — and thereby their thought processes — may be.