There are ongoing efforts for translation to Spanish and Arabic and there have been previous work on Chinese that could be .
Some parts of the application can be translated already, while other parts require some software development work. See some more information here:
I think right now what we miss is software engineering effort to review/update this pull request for the latest Slicer version and get it integrated into Slicer core. It could be done either by finding a volunteer (preferably by someone who speaks Chinese) or by giving a contract to Kitware.