Subtitles are disabled by default in Prince of Persia: The Lost Crown.
 
To enable subtitles:
 
•  Open the main menu or open the pause menu and select "System".
•  Choose "Options" and then "Display".
•  Locate the Subtitles line and tick the option to enable it.
 
You can disable subtitles again at any time by following the steps above and unticking the option.
 
From here, you can also change the following settings:
 
Alternative Font
Subtitle Background
Text Language