If you want to translate a game for yourself, follow Suryujin's suggestion and edit the original files.
If you want to help the developer and make the game multilanguage instead, I recommend you to grab the
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(it's free!) and generate the translation files.
In short, the SDK will scan the whole game and will create some text files inside the "game\tl\german" folder. In those files are listed all the strings of the game menus and dialogues. You must open the files with Notepad++ (or another text editor that supports UTF-8) and translate the strings. Like this:
Read the
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and
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. If you speak French, there is also
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.
The code in the spoiler is from
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: get a copy of the game to better understand how translations work.
Edit: to avoid any conflict, I think you should use the same SDK used by the game developer. At the end of the download page, there is a link to the older releases. The version used by the game dev is stored inside the file "game\script_version.txt".