Sorry to disappoint, @Jessica. 🙁 The lack of “true” track changes in WordPress is indeed a weakness of it.
There might be plugins out there that approximate the functionality, so definitely search around for some plugins that might do this—I don’t know of any, and we on our team literally just stick to Google Docs for composition because of these lack of features in WordPress, so it’s a tough problem to solve…but I wish you the best of luck with trying to solve it! 😀
I’ll close this thread for now; open a new thread any time if other questions/comments/concerns arise.
Sincerely,
George