To see the actual change that was made between any two edits, select any pair of edits and then click "Compare selected revisions" (at the top of the list). That will give you something like this:
In this case, you can see how the description in Brazilian Portuguese was changed.
You can use these comparisons to see what an editor has done to an item you're working on. It's also how your trainer can see what you've contributed to an item, even if another editor removes it. That's why you should never panic if your contributions get removed!