In Harry Potter and Torah I wrote a chapter on speaking animals, titled Talking Snakes and Human Souls, discussing the power of speech, the uniqueness of the human soul, and talking animals. In the course of this discussion I note that Eve may have been the world's first parselmouth.
Now I see that the ParshaBlog has written a very in-depth article titled Did Chava Speak Parseltongue? on the subject of talking animals. Definitely a good read for those interested in what Jewish sources say on the subject of talking animals.