I always wanted to know what animals were saying. Take dogs for example: I know they aren't just barking to be barking. They have to be trying to convey a message of some sort. When one dog sees another dog outside and they continuously bark at each other, I know they have to be communicating with each other. Dogs aren't stupid; if we can teach them to associate certain actions with different words and phrases, I'm sure they can communicate via barking. The only problem is, we just don't understand them.
I'm not sure if anyone has done it or not yet, but if someone was to study the pitches, lengths, patterns, and volume of dog barks, they could probably associate most of the distinct barks with some sort of meaning. It would take a lot of work, but I'm pretty sure it could be done. But even if it was done, how the results could be used to help dog owners, I don't know. Most of these barks wouldn't be distinct enough to tell just by listening, but using voice recording programs to actually study the sound waves.
Either way, I think animals have their own languages and with lots of studying and observation, we could get the gist of them.