Val, in my opinion, this is definitely an appropriate question and a good one. As far as I know, there's no add-on for the Audible app, but the Audible website works pretty well with NVDA. I hope that answers your question.
--
Abbie Johnson Taylor, Author
http://www.abbiejohnsontaylor.com
http://abbiescorner.wordpress.com
abbietaylor945@...