I've had this happen, here's a DJ excerpt from about a year ago:

"I also had a dream in which I was wandering around and an entity not directly there spoke to me. When it spoke I would see its blue form in my mind's eye (which I simply can't describe), and it also spoke in another language. It was no human language though--it was more akin to consistent gibberish. By this I mean it was a language, but not like any I've ever heard, most of the words sounded like gibberish but it was clearly a language. Somehow I knew what it was saying when it spoke to me telepathically. I never spoke back to it for some reason, I only listened. The only word I remember it saying was "moog"."