Sure,
Here we have a wiki page on how translation modding works. In short:
Create an add-on, using the Divinity Engine. (
Here's how)
1. Use the localization files in the Engine installation (~DivinityEngineDataPath~\Data\Editor\Localization) to create your own translation. With the provided spreadsheet and script, you can systematically translate all the game's lines from English to something else.
2. Place the created translation files in your project folder.
3. Publish your project.
4. If you mod existing files (e.g. you put the Spanish translation in files named after English/German [English.xml, etc.]) then people with that language setting will automatically switch to your Spanish translation once they enable the mod.
5. If you make a new language, people need to override their language.lsx file manually to set their system to the new language.
Don't hesitate to ask if you need some more information.
Sincerely,
Kevin