The translated file would either be a replacement of the '..\SteamApps\common\Divinity - Original Sin\Data\Localization\English\english.xml' file, or a different xml file and change to the language.lsx configuration file in the Localization folder. This file can be edited in any text editor.
Thanks but the localizations are always done like this? I mean, these sentences are placed disorderedly, therefore, it will be difficult to understand the meaning of them and leads to a large number of translation mistakes.
If the former translations were finished in the simple way as I mentioned, that might explain why there are a bunch of problems in the French edition.
I would rather help doing this in a more proficient way but guessing the meanings of the sentences blindly.
