Over blown.. This specific project failed to achieve its objective and that was the reason they shut it down. AI did not invent a new language. It was tasked to communicate in english but it started using english words that made no sense. The two bots that "communicated" didn't really attain their objective either. That's why they shut it down as it was useless.
Trust me, if FB has an AI that's really capable of conversing in efficient manner. They'd never reveal it in public. They can make billions out of it.
on a simplistic level - computer programs already talk with each other in their own language aka their own protocols for various needs. they don't need to invent their own language based on English words. I reckon it was just an ai experiment that didn't work out and shutdown. blown way out of proportion that they had to shut it down just in time before the ai started bitching about humans.