Facebook shut down a pair of its artificial intelligence robots after they invented their own language.

Researchers at Facebook Artificial Intelligence Research built a chatbot earlier this year that was meant to learn how to negotiate by mimicking human trading and bartering.

But when the social network paired two of the programs, nicknamed Alice and Bob, to trade against each other, they started to learn their own bizarre form of communication.

The chatbot conversation "led to divergence from human language as the agents developed their own language for negotiating," the researchers said.