dolphins use sonar to geolocate and find food. The sonar pattern used also depends on whether they are navigating, searching for prey or attacking. When a dolphin "tells" where to go to find fish, it will play back a stylised summary of the sonar imagery from navigating past the steep cliff, to "seeing" the school of 1kg macrel, to the successful attack.
This 3D communication is efficient and fast, and connects directly to the visual part of the brain. Powerful and emotional imagery can be communicated well.
Humans 1D voice communication compared is inefficient, indirect and lack precision and descriptive elements.
"Riding a bow wave" is a 1D sequence of sound that has very little info or precision compared to the sonar echo of actually riding the wave.
Humans should probably try to speak sonar, rather than try to dumb down a dolphin to speak human