I use the opensource and free version of winmerge. This is (imho) the ideal tool to compare folders,files etc.

But to put it back on topic. I found the NEW_LANGUAGE_CHANGES.txt and LANGUAGE_CHANGES.txt-files, but I find this a very unfriendly file to read for humans. A visual aid in the actual language file would make much more sense, because then I know where to copy and paste it from the original file. I speak for myself, but I can guess there are more people around here, that don't have a comiler-like application to generate an updated language file. Or is there an application available that takes the language files, takes the txt-file and updates them according to the changes?