I have the RU version, changing the language is easy, all you have to do is copy over a few files and that's it.
The only difference between different language releases are the actual language files. As with most games, the language isn't hardcoded into the game so changing it is as simple as replacing or adding files. Apart from that there is no difference, it's still the same game underneath and you pay less money and it takes you less than a minute to change the language and add the files needed.