The Simplify Words slider bar has three levels. By sliding the bar to the far left you can select Original, the middle is the Default settings and Maximum Words is on the far right.
Original: You see the orignial text, but words that can be simplified/leveled are in italics. By clicking on the word in italics you can see it simplified . (If you have a language selected for translate clicking on the italics a second time will translate the word)
Default: Simplifies text and tries to keep the fluency of the reading. ( Words in italics can be clicked on to show the original text, simplifed text, and translate if a translate language is selected.)
Maximum Words: Levels the maximum amount of words that we can simplify in the text. (Some words are very difficult to simplify and may affect the fluency of the reading)*
*If you are having trouble following the fluency of the simplifed text when it is set to Maximum Words try the Default setting.