Swiftkey can be disabled by picking another keyboard or you can uninstall the program altogether. Either way, it will be as if it never existed. To change the keyboard, pull down the shade while the keyboard is open and choose the option to Select Input Method. If you don't have that option, then long press in any typing area and the Input Method chooser will pop up.
I'm not that familiar with audiobooks (I'm more of a podcast kind of guy), but everyone I know swears by Audible