Facebook might have accidentally gotten a little closer to answering Phillip K. Dick’s 1968 question of whether androids dream of electric sheep. The social media giant just shut down an artificial intelligence program after it developed its own language and researchers were left trying to figure out what two AIs were talking about. The AIs had found a way to negotiate with one another, but the way they debated used English words reduced to a more logical structure that made more sense to the computers than to their human observers. What at first looked like an unintelligible failure to teach the AIs to talk instead was revealed as a result of the computers’ reward systems prizing efficiency over poetry.

There are plenty of computer “languages” developed y humans to help computers follow human instructions: BASIC, C, C++, COBOL, FORTRAN, Ada, and Pascal, and more. And then there is TCP/IP, which helps machines “communicate” with one another across computer networks. But those are all linguistic metaphors used to describe electronic functions, rather than the vocabulary we need to discuss the huge leap forward an artificial intelligence developed by Facebook recently made. The goal was ultimately to develop an AI that could communicate with humans, but instead the research took a left turn when instead the computers learned to communicate with one another in a way that locked humans out by not following the rules of English.