THE DEVICE called “CHAT” is still a prototype, and, strapped to the chest of a diver, it looks like it was bolted together in somebody’s garage. But Denise Herzing is hoping it will allow her and her colleagues at the Wild Dolphin Project, after three decades of research, to speak with free-swimming marine mammals. She’s not interested in the kinds of signals that pass for communication at any seaquarium, which are more or less on a par with dog training: do the trick, here’s a fish. The new device “is designed to really be two-way,” Herzing explained in a recent TED Talk. It’s built to “empower the dolphins to request things from us.” But would those free spirits really care? Dolphins have big brains. “They’re probably close to our intelligence in many ways,” said Herzing. And since ancient times they’ve been mythologized as kindly kindred beings in the sea. But, notwithstanding their anthropomorphic playfulness, they’re from a world that’s not ours. Even if commonly intelligible words (or beeps or whistles) can be found, every context would be wildly alien. And looking at the upturned corners of the dolphins’ mouths, one has to wonder: have they been laughing at us all this time?