I listened to an entire Kindle book this way many years ago. I imagine / hope Siri's screenreading only got better in that time. I think you need to set the Ki

I listened to an entire Kindle book this way many years ago. I imagine / hope Siri's screenreading only got better in that time. I think you need to set the Kindle app to continuous scrolling (in which case it won't work with older books), then you trigger the iOS screenreading shortcut, and off it goes.