From the books, we know that people can be Transfigured into animals, but the only way to retain their human brain is to become an Animagus. But what about the other way around? I know we have never seen it, but would it be possible to turn an animal into a person? Would they be capable of speech, even if they couldn't understand the human language? Would they even remember a time before they were human?
Can I hear thoughts and opinions?