Incorrect. There are multiple definitions of language, not one. As another commenter pointed out, if you make the definition broad enough it loses usefulness.

Incorrect. There are multiple definitions of language, not one. As another commenter pointed out, if you make the definition broad enough it loses usefulness. > it’s anything that can have a grammar, "Can" have a grammar is not restricting. "Does" is the correct verb, and that hasn't been proved. > All you need is something that can form a sentence and something that can parse it and the thing going on between them is language. OK, you've actually drawn out an important point. CAN the fungi form a sentence? I can encode the 2nd sentence in "War and Peace" into polypeptides, but the polypeptides are still just an encoding of the language I picked (English? Russian?), and it doesn't make exchange of polypeptides by any other organism (even grad students!) a linguistic exercise.