The New Yorker – Language is said to make us human. What if birds talk, too? – no unpaywalled access so in lieu of please see this extensive excerpt and analysis via UPenn Language Log – Birdtalk: “Of course, we’ve been through the business of animal communication countless times on Language Log, but where this article differs from previous discussions is that it concentrates on content and consciousness rather than vocables and sounds…Bird vocalizations are usually divided into songs and calls, but these are wobbly categories. What is designated a song in one species may be shorter in duration than what, in another species, is termed a call. Onomatopoeic groupings such as tseets, chirrups, rreeyoos, seeew-soooos, and dahs are also indeterminate: people transcribe the same sounds in different ways, and no bird version of the Académie Française exists to adjudicate. The vocalizations of birds are fundamentally incommensurate with human ones. We have a larynx and two vocal cords; they have what’s called a syrinx, which is a bit like having two larynxes that you can use at the same time…”