Communicating between species isn't something that only has to take place between space-faring civilizations. There are plenty of species here on our home planet that communicate using a variety of sights, sounds, and smells. We're only starting to unlock the secrets of how to understand and respond to these types of foreign languages. Researchers at the SETI Institute think that doing so might be a good test for whether we'll be able to communicate with extraterrestrials if we ever get the chance to.
