A team of scientists from the SETI Institute, University of California Davis and the Alaska Whale Foundation, had a close encounter with a non-human (aquatic) intelligence. The Whale-SETI team has been studying humpback whale communication systems in an effort to develop intelligence filters for the search for extraterrestrial intelligence.
It would also be a breakthrough to know another species has a greeting, something which requires regular interaction with others and thus a form of society. If there is a consistency to the communication then there is also a potential for culture. If there is an equivalent of “hello” it would have the potential of changing everything.
Anthropology would be a broken up into species specializations and Cetaceopology would become a thing. Linguists will also have species specific terms for sounds outside of human vocal ability. AI will be trained on non-human speech. Everything will be different.