You will have to fly blind a bit, but remember that the Spanish word for language is "idioma" and the Spanish word for English is "Ingles" - Here is a link to the user manual that will help you - Sansa does have a Spanish version of the manual if you want to compare. Eventually, you want to find this menu/setting:
This will reset the player to its original factory settings.
1. Press Menu to return to the Main Menu.
2. Move to Reset All
and select it.
3. Select Save
to reset to factory settings or Cancel
-Tha Mp3 Doctor