You say "the only reason," but I'm not sure. I think one barrier may be that we're not that interesting to them. Perhaps, rather than sending literal-minded sc

You say "the only reason," but I'm not sure. I think one barrier may be that we're not that interesting to them. Perhaps, rather than sending literal-minded scientists to attempt communication, we ought to send poets and musicians. I read of a recording of an upset, irate dolphin's sounds. When slowed down significantly, it was clear the dolphin was mimicking it's trainer's reprimands. So, one clue is that their processing speed is way higher than ours. I also read of a researcher who set out with a box that could make dolphin sounds, and she wanted to teach dolphins to say names she has made up for three objects, with disappointing results. But I'm wondering... these are creatures that can be taught a command that means "innovate" - do something different that you haven't shown me yet today. A rule of their language might be never to use the same word twice. Also, dolphins are aware of one another's sonar. So, they would never need to vocalize "Look at that over there." They already know what pod-mates are paying attention to. Possibly they wouldn't find it interesting to use nouns to refer to things that are already obvious on the pod's echolocation radar. Their verbal channel might deal with less concrete things like mood, nuance, intuition, and humor.