Hi there,
I checked the Blender manual again and it uses Sphinx. It supports multiple translations and people are able to download the manual for offline use, which is great.
The only things that worry me are that it would be difficult to deal with images on different languages. I believe that we could set as the default manual language the English language since it is the most widely accepted and supported in software.
I was just wondering if new languages, based on the English manual, would use Inkscape images in English or if they would like to retake the same screenshots in different languages? In the Blender manual they kept everything in English even if the manual is written in German or Spanish.