I am sure the author would love what you said that about hearing the dialects and accents. She said for her the cadences of the dialogue/dialect were so important to hear as she wrote them. She could hear them deep inside of her as she wrote. What a great perception you have to enjoyed that additional layer to the book withe the audio :).
I am *really* late in this post, but I am reading this book now, and thoroughly enjoying it.
What struck me about the dialect in the book, besides it being very well done, was the lack of outcry from liberals, labeling it racist.
Your friend is very talented. I look forward to reading more of her work in the future. :-)