Well, that might be true of human language—though I’m not sure about the case of sign language for apes in captivity. Part of the problem is the physiological ability to make the sounds needed for human language. The other species simply lack that ability for the most part.
But how about flipping that view. Has any human been able to learn any language any other species might use? Sea mammals (dolphin, whales) appear to have some form of vocal communications. Similarly, I’ve at least heard stories that wolves also seem to communicate. Anecdotally, I have witnessed what I would take as am indication of communication between two of the dogs we used to have.
Those are decent points. Not enough to sell me but enough to make me take it more seriously.
Those are decent points. Not enough to sell me but enough to make me take it more seriously.