I haven't done comparisions specifically for translation purposes, but below are a couple ideas for file/text comparison that might help.
You could try Beyond Compare, a powerful file and text comparision tool. They have a 30 day trial available.
Or if you are using source control, that will probably have some sort of comparison tool that lets you compare different versions.
(I sort of have an idea in my mind that the translation memory used by the translation companies can mark differences automatically too, but not sure on that one.)
Thanks Amebr. I was hoping that there might be a feature within RH but I haven't found it so I guess not.
We are translating in-house and so are without the benefit of a proper translation company and their tools.
Source control is my next thing to research...
Since this is in house, there is one way you could set up that may help. It depends on how familiar you are with See Also Keywords and See Also Controls.
What you could do is create a See Also Keyword. Perhaps name it "Attention". Then as you edit or add new content, you would assign the affected topic(s) to the keyword. Then you would have a topic that has a See Also Control that is linked to the keyword. In order to "see" what needs attention, whomever is working with the content would just open that topic and click the See Also Control. All the affected topics would then be listed. Essentially, you are just keeping track as you go along.
Note that this isn't automated nor is it foolproof. It would require being diligent to assign topics to the keyword. But once everyone has become accustomed to it, it should be easier than running a comparison application and trawling through code.
Thanks Rick. We may end up having to do something like this so that's a useful suggestion.