When choosing between talking natively with animals or speaking fluently with humans (also known as speaking all human languages), I would much rather speak with animals. I understand how important it would be to speak with all human beings in the works for many however currently it is possible to speak multiple languages fluently and speak with millions of people that is something that I think there is not need to give it a big thought, we just need to search for internet about how many human languages many people.
On the other hand, when looking for information about human-animal communication, we always struggle to understand how animals do what they do. I even question if we understand animals at all. There may be certain wisdom, valuable lessons and, actually human kind and all alive beings would benefits since we would learn more about how to cooperate, create a better society and even improve our lives, to mention a few benefits.
For those reasons, if I could learn how to communicate effectively (so we could comprehend animals), that would definitely be my choice.