Well, this is the Melissa Show, and I hereby give you the gong, Mr. Deep Knowledge. Other animals may not have speech, but they sure as shooting have language. We just don't happen to comprehend it, so in our highly intelligent human way, we say they don't have it. The reason we don't get it is that it's a physical language, and we are so mouth-oriented we even assume our pets are born knowing English: there's the guy talking to his dog--"Hey, now I thought I told you to come here!"--and looking miffed that his dog didn't answer back in a nice way.
The fact that we don't believe animals (I mean, other animals) have language puts us in the position of colonialists who find the natives to be little more than savages, speaking as they do in those unknowable grunts. But logic (oh, precious, precious logic) decrees that it is impossible for humans (and especially highly social ones) to have developed language alone among animals. Please, put this idea through the logic mill and see how it turns out.
Then I defy anyone whose logic is still malfunctioning to sit through a lecture such as the one Suzanne Clothier delivered recently in Saugerties, New York, and come out of it with an intact belief that canines don't talk. I only left there thinking I didn't know the half of it--and I already knew I didn't, due to my appreciation of, nay astonishment at, Brenda Aloff's extensive Canine Body Language: A Photographic Guide, which I believe should be the operating manual that comes with every puppy. She flashed slide after slide of dogs interacting, clearly communicating definite and not always simple information, on which she had overlaid colored lines to highlight the aspects of the body--compression, angle, tension, orientation--that were doing the talking. And she narrated each one: "Helloo! Wanna play, wanna play, wanna play?" [you can hear the black lab's accent here, right?]; "Listen, idiot, you obviously don't know how to ask politely. Get out of my 'personal space,' OK?" No matter how baroque, how TV sitcom, how Ann Landers it sounded, I would bet my last dollar that that was exactly the substance of the conversation.
She said that, in her experience, it was pathetic how few dog trainers, much less simple dog owners, knew the first thing about reading dogs' language. I believe it, too. It's horribly sad to think of a dog, or anyone, desperately trying to convey something to a person who can't hear them. For the emotionally unstable among us, it's a recurrent nightmare. And we make our dogs live in it all the time.
Ah, but our language is the language of Shakespeare, Milton, and Eliot; it has risen so high! Yes, and physical language is the language of Balanchine and Goya. Right? Go to the dog park. You might see some beautiful ballet there. Right now, Nelly and I are going to take a walk in the cornfields. I pray the rabbits are hiding and the fawns are well taken care of. Or else Nelly will have something quite concrete to say to them.