Yes, science does speak for itself. But usually only to other scientists!

Scientific jargon is a language few non-scientists speak or understand. So the natural reaction is to tune out, become angry or confused, or – worse – completely misconstrue what is being said.

In her now-classic article Improving How Scientists Communicate About Climate Change IPCC editor Susan Hassol provides many examples of how when scientists say "x", lay audiences hear "y."   For example, when you say "positive feedback," most people think of a compliment or "pat on the back."   In contrast, almost everybody will understand if you say "a vicious cycle" or "chain reaction," which in most cases means essentially the same thing.