You can define an accessibility shortcut by following these instructions: http://help.apple.com/iphone/9/#/iph3e2e31a5

VoiceOver is a particularly help function for dyslexic students to add an accessibility shortcut. When the shortcut is used in the Kindle app (some books have restrictions on text-to-speech) it will read the text out loud. You can also define your preferred reading accent and select an enhanced quality voice that is more naturalistic. Increasingly Kindle books support Speak Screen which is even easier to use than VoiceOver, so it is worth trying that first to see if it works.

Bonus tip: the Kindle app now allows copy and paste. So not only can you make notes and highlights in the book itself but you can also use app switching to copy citations to notetaking app. Please note that split-screen multitasking is only available on newer iPads.