I think it is a common mistake; I know I do it too. I also say/think the wrong word, and, often as in your broke/brook example, the words will start with the same letter or be the same number of syllables or have some other significance. I have even dreamed and used the wrong word for an item only to realize it when I woke (calling one musical instrument by another's name as in "French horn" for "oboe"). The dream was about my college roommate's boyfriend/husband and I was very aware what instrument he played in high school, etc. but in the dream I named it wrong.

I think the words we choose, especially the "wrong" ones, can be very much about what we are thinking and, if they have an unconscious element going on, we can choose something else, like with a Freudian slip situation? Maybe you were thinking of painting a water scene and reading about artists and mixed up the combination that way, something like that or something even more subtle like wanting to "brook" the distance with a bridge of some sort so there are no broke artists :-) We daydream just like we dream while asleep and maybe your eyes were reading one way and your unconscious working somewhere else, LOL.