title_body: How to manage translations when self-publishing (in-house translation)?
upvoted_answer: I recommend you consider to move to an explicit mark-up system (LaTeX, reST/Sphinx) that allow you to:
  
  
  split the work in smaller files that are automatically combined
  use revision control (Mercurial) on the files so you can see what changed between versions (roll-back of changes, easy differencing, have multiple people work on the same file with conflict resolution support)
  have the possibility to include more extensive comments (that will never show up in a printed version).
  
  
  You can continue to edit the files in word, you should just not use its What-You-See-Is-All-You've-Got features for layout and styling.
  
  This might seem overhead if you never used tools like LaTeX/Sphinx. Having persistent predictable output is something that will be invaluable for anything serious (more than 10 pages I would say). I have seen academics trying to do their thesis in Word (and more recently LibreOffice) and be driven up-the-wall by documents breaking after a section or picture was moved around or missing hyphens while exporting to PDF.
  
  Revision control systems like Mercurial allow you to save often, mark specific revision and compare those against the latest (or each other) and push your whole writing effort to a (private) remote copy of the full repository (with all the revisions) in an efficient way. This is much quicker than keeping track of revisions by hand ( e.g. saving as book_20131225.docx) or making off-site backups in any other way.
  
  The people at TeX-LaTeX StackExchange are very helpful and for revision control you can ask on StackOverflow.