The title really explains it all 
We are going to use the new, amazing!, i18n feature on our site, and we will have a lot of pages where a bunch of stuff are repeated for different pages on the same language.
For instance, we have a page called “Houses in London” in 5 different languages, and we also want to have a page called “Houses in Berlin” in the same 5 different languages. The german pages would be largely similar, with a bunch of fields being exactly the same, and it is a lot of copy and pasting between the pages
I hope I explained it well enough. Basically, when I click copy on a collection item in the list, I would want it to copy all the language versions of that page.