I was looking for research into DOLPHIN LANGUAGE and didn't really find any.
Well, because HUMANS ARE STUPID, and manipulative.
Seriously, as you can see from this EXPLORATION FILMS clip below, dolphins think in an abstracted almost-mathematical here/not here way, BUT they're talking to humans via the human abstraction. We're making them think like us. Or tailoring a pseudo language within the dolphin's mind. This isn't dolphin-speak, it's emulate-human-speak.
We're still not yet LISTENING TO DOLPHINS and talking back to them as they do to each other, we're crippling the captive dolphin's mind via the lure of food.
Sick, just sick.