Do animals has their own language? This problem is seemingly innocent, naive, but it relates to our discussion about the "language". Some studies have shown that animals have language like human, and they also have emotions. From my point of view, laughter and joy is not the unique human ability. Maybe long before humans can laugh, the other animals already have the original form of laughter.
Animals of course have their own language, but may not necessarily with a voice to express. Different animals have different ways to expression themselves, for example, ants exchange message with antennae dancing, bees exchange message with different flying route, squirrels exchange message with their tail waving.
I own a cat at home. I really think sometimes we can understand each other. In order to built a good relationship with her, I find some ways to understand cats emotion on internet. That's petty useful.
Another example of animal language is dolphins. Nowadays, people also began to understand the language of the dolphins, rather than just think that as a discordant percussion, beat or whistle. The new study suggests that when dolphins encounter each other in the sea, they use whistles which they both familiar with to introduce themselves and greet to each other. Here is one video I found on youtube.com which talk about language of dolphins.
In the end, a picture of my cat.:)