The following gives away a minor twist about BLOOD ROCK, so if you haven’t read it, go read it and come back.
As Devin says, corprolalia, which affects Dakota’s adopted daughter Cinnamon Frost, affects only ten to fifteen percent of Tourette’s Syndrome patients in real life – and certainly many people have learned to fly with the Syndrome.
I make no apologies for Cinnamon’s fiction-friendly Tourettes; in the first draft it was “romanticized”, but during revision, even before editing, I did a lot of research and put a lot of thought into the presentation of her condition. Like many Tourette’s patients, she exhibits a variety of rather subtle symptoms that most characters in the novel never comment on or even notice; Dakota is not an omniscient narrator.
However, literature IS a poor substitute for science: no matter how good a work of fiction, no matter how well researched, it’s a made up point of data, not as good as a real teen with Tourette’s doing poetry slam or a good review article on the subject. I encourage you to read more about Tourette’s from Wikipedia, from the National Institutes of Health, or the Tourette’s Syndrome Association.