How could someone who appeared to be an animal prove themselves human?

This is kind-of a twist on that familiar “what makes us human” and “what distinguishes a human from an animal” question that makes its rounds from time to time. Have fun with it.

And the best way to have fun with it is to take it seriously. There are AT LEAST three ways to go with it—

(1) If a human were turned into an animal, (a.k.a. “Bewitched”, “Jeanie” or little Anthony Fremont but in a less isolated setting)—how could a person get their human rights recognized or restored?
(1a)—Humanlike animals, such as monkeys
(1b)—Common, likeable domesticated animals—dogs, cats, horses, birds—some of which (birds) might retain the ability to speak, or otherwise understand and communicate
(1c)—more exotic animals such as an elephant or rabbit or snake
(1d)—something monstrous or
(1e)—truly disgusting and repulsive but not human or even a known or identifiable animal

(2) What if a person (seriously—because of a medical condition or transformation/transmutation) LOOKED very much like some other primate ??? What other than speech might prove their humanity?

(3) (the most serious of the three possibilities mentioned here) If a Chimp, Gorilla, or other primate COULD obtain human or near-human sentience, could or would they be allowed to pass as human in society?

(4) I’ll throw this in, too—the movie “A.I.” brought this up—what about androids and machines—could they ever feel human emotions and/or be recognized as human?