What does being "well spoken" say for someone in terms of intelligence?

Since I was young I've been told that I'm "well spoken" but I've never felt particularly smart. It takes me a long time to process things and I'm not particularly quick witted. I've always been an avid reader, but only an average student but people always assume I know more than I do and I wonder if this is because I supposedly speak as though I know what I'm talking about, even when I don't. Do most people associate being "well spoken" and being smart?