> The authors compared animal and human communication, eliminating the aspects of vocalization that are shared by both, and concluded that one operation alone distinguished human speech: recursion. In the course of working on the article, Fitch grew sympathetic to Chomsky’s ideas and became an articulate defender of the theory of universal grammar.
"(…) distinguished human speech(…)", if you think about it, that's a weird assertion/assumption to make. The idea, that there's a clear line between human and non-human communication, as if this was something binary.
We humans have this weird concept, that there's "something", that makes us fundamentally different from the rest of the animal life on this planet. Yes, we've got the largest impact on the biosphere, we can reason about it. But if you were to track back on the coginitive abilities of our evolutionary ancestors, I'd say it would be very difficult to put a hard threshold in the phylogenetic tree, where suddenly a whole subset of means of communication discretly vanishes.
Just my 2 cents…