The European Language pack is a feature that allows you to play in a different language than the language in which you bought the game. If you bought an English version of the game and you want to play in Spanish, then you will need to download and install the Spanish Language pack to in order for the game text to appear in Spanish.
The downloader is 600 KB to 1 MB in size and the language file itself is around 250 MB.
For any further information about the ELP (installation, features, etc), please read the ELP FAQ here.
For questions about choosing your language and realm, be sure to check the realm language information here.
Downloaders
Click on the version you want to install (Language and Operating System).
