Soundclip of built-in accessibility feature called VoiceView Screen Reader which reads everything on the screen.

Yes the understandability is not quite as good as the Audible actor speaking but this would work on most text books without purchasing an Audible book. The downside is learning the gestures to control it as there is some learning curve and its not as easy as the older Kindles were.

Click "download" and choose audio app to play the sound.