A recent The Scientist article talks about the appalling lack of understanding of key scientific concepts and terminology among science teachers and scientists! If even those who work in the field can't follow exactly what you mean when you use terms like theory, and hypothesis, and fact, how can we expect a non-scientific audience to follow?
It is incumbent upon us, as science communicators, to be familiar with our audience, the terms they know and use, and what those terms mean to them. Work with your audience, not against them, and recognize that does not mean you are "dumbing down" the science. When your 14 year-old uses different words to talk to you and your friends than she does her friends, is she "dumbing it down" for you, or is she communicating with you in a way that you intuitively understand?