I have done somthing simmilar with training materials. The process should work the same for documents.
In training you have the learner indicate at the begining ( or they can flip back and forth in the class) what language they want by selecting a flag ( or you can use the language indicated with native characters). I find that flags work best except for 508 courses.
This sets a variable that then pulls in the content in the language selected ( text and or voice). The key is to have the formats defined. I created these in a text file that is then used as a template to create the various translations based on defined sizes/times that would display in the actual class.
For text you would use the same approach. In MS word you would have the summary page of the document show the content summarized in differant languages. At the end of each summary section provide a link to the native document. There are more exotic ways to approach this but simple file structures with links will work. There are various platforms that you could use for internal and external access.
The key is to ensure that the translations are correct. Deionized water can be translated in Mandarian as "devil water" which here in the US implies that it is alcohol. This error could have serious results.