There is this believe that some human beings have the capacity to talk to ANIMAL.
Is this real or they are all fables?

Anybody can talk to anybody/anything. I can talk to my PC, teddy, bed, chair.
I talk to the mosquito dancing in my room, asking it to leave or I strike it.

I think You meant to ask - Can a person communicate with animals?

Again, When I tell my dog to sit, it actually does. That means, it understands me.
When I ask it, if it would like us to have a walk, it lies on its back and begins to roll happily, while wagging its tail. I get the message, it likes the idea.

That way, we've communicated. I talked, it responded and I understood.

Question answered?

Question answered? NO,
I mean Can people hear animal's voice? sort off

When ma dog makes the bau bau sound, I hear it. So? 

Animals do not talk like humans do. Better put - They don't speak the languages we speak. However, they transmit informations, using sounds, body language etcetera.

Question answered? No? Explain better, what You'D like to know. Use example(s) if necessary.