Another problem with common names for cetaceans is that they come from whalers' terms and are based on size, not on how the animals are related. With scientific nomenclature, each species has its own unique name that is recognized in every language.
Scientific names are always in Latin and often describe some attribute of the particular species.
The mahi mahi, which is sometimes called a dolphin, is a fish, not a cetacean. Whales, Dolphins, and Porpoises.