If language naturally evolves to serve the needs of tiny rodents with tiny rodent brains, then what's unique about language isn't the brilliant humans who invented it to communicate high-level abstract thoughts. What's unique about language is that the creatures who develop it are highly vulnerable to being eaten.

Animals in Translation: Using the Mysteries of Autism to Decode Animal Behavior (ed. Simon and Schuster, 2009) - ISBN: 9781439130841