Translation packs are now available in NirLauncher download page
The download page of NirLauncher package now also allows you to download all translations of the desired language in one zip file. After you download the right translation package, you can extract it into the NirSoft subfolder of NirLauncher package, and then every utility that you run will be loaded with your language, as long as the translation for this utility is available.
The translations packs are automatically created and updated each time that a new versions of NirLauncher package is released.
For now, I added the translation packs for 10 languages only, but it's possible that more languages will be added according to users requests.