ESS File

An ESS File is a text file used by ESP/ESM Translator, a tool used to translate mods for The Elder Scrolls V: Skyrim, Fallout, and other Bethesda video games.

About
It contains a database that allows players to translate a mod's text into other languages. EET files are primarily plain text files, so they can be opened and edited in any text editor.

xTranslator
.ESP and .ESM files are game data and plug-in files often used to mod Skyrim, Fallout, and other Bethesda video games. Many of these files contain only English text, which can make them difficult for non-English readers to use.

ESP/ESM Translator allows gamers to translate ESP and ESM mods' text into other languages. To do so, the gamer must first acquire or create an EET file, which is a translation database that contains multiple languages' versions of game-related text. For example, an EET file might contain multiple copies of a game's dialog and menu text written in different languages.

After a gamer acquires an EET file for a game, they can attempt to automatically translate ESP and ESM mods using the EET file and ESP/ESM Translator. Gamers can also manually write translations and store them in an EET file. Then, they can apply those translations to a mod's text.