The book’s advertisement looked good.  It purported to be a well-researched description of the different ways people talk in different parts of the country.  It turned out to be a thinly researched and narrow sampling of different word choices, accents, slang expressions, and word etymologies.  Too much blank space, not much nuance, and too few examples.

What was in the book was interesting, but I came away not quite trusting its assertions.