Biography
Many cartoons have them — some animation companies have made their entire core casts out of them. Very simply, these are animals who talk.
The term "talking animal" is typically used to describe any animal character that talks, whether it be a Nearly Normal Animal or a Funny Animal, but there are so many examples of animal characters that talk, this page will only cover characters that aren't:
A Nearly Normal Animal, which can converse with other members of its own species or even members of other non-human species, but not with humans.
A Civilized Animal that shows some human mannerisms, but otherwise occupy their species' natural role.
A Funny Animal who has many human mannerisms, making them practically a human aside from being an animal.
This page will only include characters that, despite their ability to speak, are still animals in almost every other way, particularly when it comes to instincts, priorities and motivations. They very rarely wear clothes, and they are often vocally proud of the fact they aren't human. They may even choose to talk to no one but a single human, who typically finds this very disturbing. They may even break the Fourth Wall and talk only to the viewer.
A good comparison: Ralph the mouse (from The Mouse and the Motorcycle) is a Civilized Animal; he lives in a mousehole, dodges cats, and runs around naked (save for his fur), yet he enjoys motorcycles and regularly talks to the human boy Keith. Mickey Mouse is an example of Funny Animal; he lives in a house, drives a car, wears clothing, and sprays his garden with pesticides (think about that for a second). They can easily hold down a conversation with any human member of the cast. They are a lot better at it than the Speech-Impaired Animal. It's not like every human Speaks Fluent Animal either; the animals themselves are able to talk and that's just the way it is.
Another good comparison: The animal characters in Tarzan are Nearly Normal Animals; they can talk to each other but not to normal humans. The animal characters in The Jungle Book are Talking Animals; they are able to talk to other human characters besides Mowgli.
Like many Speech Impaired Animals and Nearly Normal Animals, many Talking Animals lack hands and walk on all fours, negating the possibility of performing many human tasks and behaviors. A few examples are bipedal if their species is flexible enough. However, when required by a joke, the Talking Animal can sometimes act like the more anthropomorphic Civilized Animal or Funny Animal.
Since these are otherwise normal animals who are able to talk, the issues of Furry Confusion don't usually come up. The issue of What Measure Is A Nonhuman, however, is far more likely to affect a Talking Animal than a Funny Animal. That said, Talking Animals are likely to voice just what they think about humans...
The Fairy Tale is more likely to feature a talking animal than a fairy. (Although they do often turn out to be humans under a curse. Or even ghosts.)
Polly Wants a Microphone is a specific sub-trope for when in fiction, most animals can’t talk, but parrots can talk instead of just mimicking human speech.
Lots of verbal jokes involve talking animals, with the humour usually deriving from a trait of that animal or a pun based on the word for the animal. A common subversion of these jokes is to replace the punchline with something along the lines of "Holy crap, a talking horse!" See also Not in Front of the Parrot.
Fun fact: As ridiculous as it sounds, there are some books like Charlotte's Web that were banned in some areas of the U.S. because they had talking animals in them.
Many Weasel Mascots, Non Human Sidekicks, and Team Pets are Talking Animals. Talking birds are a separate subtrope. Compare Intellectual Animal, Sapient Steed, and Uplifted Animal. For the next step "up" in the latter, see Partially Civilized Animal, Civilized Animal, and Mouse World. See also Sliding Scale of Anthropomorphism.
Don't expect the problem of the animal's vastly different (or completely absent) vocal tract to be explained.
Compare Animal Talk. Contrast Pantomime Animal.