Basically, it or they (dunno if it was 1 or 2 softwares) started to use some english-babbling but it was enough to communicate on the basic level. I do belive they could develop sentience if running for a certain period of time.
And funny Tay posts would have been least of our problems.
Good thing is that if these AIs get implemented and try to take over humans with weapons and such, they will always fail. Because these robots would be a bit too expensive to really spread all over the globe. Besides, Russia wouldn't be fooled and implemented it as well.
But if they were to try doing it like illuminati... I don't know if we have a chance. Kikebook should be shutdown.