"It's a very interesting finding that encourages further research, because they are using whistles as referential signals -- that's what words are," said Sayigh, of the University of North Carolina Wilmington. "Dolphins appear to be using these arbitrary signals to identify another dolphin."
As a general rule, I don't agree with animal rights activists. Dolphins are an exception: I think it's possible they should be treated as moral agents with rights, and that the only reason we haven't recognized them as such is our inability to communicate with them. Their cognitive abilities are impressive: Tool use, self-awareness, and now the use of verbal names. Perhaps more importantly, the stories of human divers in trouble being rescued by dolphins, who sometimes go so far as to attack sharks to keep them away from the humans, suggest at least the possibility of moral development, in addition to cognitive development. Given the possibility of moral agency, I'm inclined to treat dolphins as sort of provisional-persons: I can't really grant them full person-hood without more evidence, but at the same time I think we ought to avoid really egregious abuses, such as hunting them for food/sport, just in case.