One time I tried to talk to a crow by telling it to caw once for yes, twice for no.
Grabbed its attention with a friendly greeting, to which it turned and looked at me, waiting for what I'd say, keeping eye-contact and everything.
I asked it if it actually was a crow, since I wasn't sure. It cawed once, and patiently waited for me to speak again, looking at me all curious. I said Thank you, and it looked like it nodded.
Obviously I have no idea if that bird actually understands that crow is what humans call it, but it did feel like I had an actual conversation with it.