Talking animal

A talking animal or speaking animal is any non-human animal that can produce sounds or gestures resembling those of a human language. Several species or groups of animals have developed forms of communication which superficially resemble verbal language, however, these usually are not considered a language because they lack one or more of the defining characteristics, e.g. grammar, syntax, recursion and displacement. Researchers have been successful in teaching some animals to make gestures similar to sign language, although whether this should be considered a language has been disputed.
Possibility of animal language.
The term refers to animals which can imitate (though not necessarily understand) human speech. Parrots, for example, repeat phrases of human speech through exposure. It is a form of anthropomorphism to call this simple repeating a language, as it has no semantic grounding. However, there were parrots that learnt to use words in proper context and had meaningful dialogues with humans. Alex, an African grey, understood questions about color, shape, size, number etc. of objects and would provide a one-word answer to them. He is also documented to have asked an existential question. Another grey parrot, N'kisi, could use 950 words in proper context, was able to form sentences and even understood the concept of grammatical tense.
Researchers have attempted to teach great apes (gorillas, chimpanzees and orangutans) spoken language with poor results as they can only be taught how to say one or a few basic or limited words or phrases or less, and sign language with significantly better results as they can be very creative with various hand signals like those of deaf people. In this regard, there are now numerous studies and an extensive bibliography. However, even the best communicating great ape has shown an inability to grasp the idea of syntax and grammar, instead communicating at best at the same level as a pidgin language in humans. They are expressive and communicative, but lack the formality that remains unique to human speech.
Research supports the idea that the linguistic limitations in animals are due to limited general brainpower (as opposed to lack of a specific module), and that words are created by breaking down sentences into pieces, making grammar more basic than semantics.
Reported cases by species.
Dogs.
An owner hears a dog making a sound that resembles a phrase says the phrase back to the dog, who then repeats the sound and is rewarded with a treat. Eventually the dog learns a modified version of the original sound. Dogs have limited vocal imitation skills, so these sounds usually need to be shaped by selective attention and social reward.
Great apes.
Great apes mimicking human speech is rare although some of them have attempted to do so by often watching and mimicking the gestures, and voices from their human trainers. Apparently, human voice control in non-human great apes could derive from an evolutionary ancestor with similar voice control capacities. These include chimpanzees and orangutans.
Cetaceans.
Some of the species of toothed whales like dolphins and porpoises such as beluga whales and killer whales can imitate the patterns of human speech.