How about:
- Save your Word docs in XML.
- Commit your XML Word files.
-
Diff using an external XML diff tool. For example:
$ git difftool -t xmldiff c3d293 498571
Transforming the XML files to have one element per line should make the check-in process run efficiently and also allow the external XML diff tool to process quickly.
References:
- http://www.kernel.org/pub/software/scm/git/docs/git-difftool.html
- http://www.logilab.org/projects/xmldiff