People that know what they hell they are talking about are able to explain something with fewer words.
Now, when I find myself meandering as I communicate I know to stop, gather my thoughts, reconsider my “outline” and try again. The result is that I do a little more “re-writing” than I used to, but also that the stuff I have to say is better and more easily digested.
Conversely, when I receive a communication from someone, the way in which they outline the problem or tell their story gives me insight into their understanding of it.
This applies to code as well. When something is well understood, the resulting implementation in code is always simpler and easier to understand/maintain/extend.