Oops, didn't notice you also made an english version
.
(copy/paste)
The post you're referring to can be found
here. Here it sais that the game changes language depending on your system settings, at least the version he bought. This does change the whole game, including menus, etc. I do not know however if the German version also has the English version on it. Safest bet would be to buy the English version, but the choice is up to you.