In FanFiction you can read stories written in different languages by following the below mentioned steps:
Step 1: Tap "Just in" from the Tab bar at the bottom of the screen.
Step 2: Tap "Filters" from tool bar of the Just In screen.
Step 3: After tapping Filters a menu will pop up. Tap "Language".
Step 4: A menu will pop up displaying list of all the languages available. Tap on your desired language and enjoy reading your stories.