I'd be less cynnical if researchers hadn't announced the same thing like 10 years ago
https://www.nytimes.com/2017/12/08/science/dolphins-machine-...
Ah this is different. The Nytimes article is about identifying/classifying dolphins from audio. This new model is about communicating with dolphins from generated audio.
The difference between recognizing someone from hearing them, and actually talking to them!