Preferred method for creating non-english wiki

Hi. Since there is no interface for adding languages - I have a question about creating non-english wikis. Should I enter documents leaving their language as 'en' (and leaving language setting in XWiki.Preferences), or better change preferences to my language and append 'language=pl' to newly created documents? I would like to avoid problems with future upgrades and possible translations. And another one question: is there a howto about creating translations of xwiki itself? I would like to create an polish version. I see, that there is htmlarea/lang/pl.js file, but it contains only few phrases. I will share my translation, of course. Richard. -- "First they ignore you. Then they laugh at you. Then they fight you. Then you win." - Mohandas Gandhi.