iTunes language is the same as your system is using.
To change the language your system is using System prefs > Language & Text.
(though I don't understand why you would complain about iTunes if everything else on your system is using the native language)
Suggestions here -> http://www.apple.com/feedback/
Chris, thank you for your reaction.
However this is not the case. What I mean is that small details are in the native language where you live (eg Dutch in Holland, German in Germany or Portuguese in Portugal).
Example: if you want to put a song in your wishlist it says: (where I live) "adicional a lista desejos"
Also the top menu in iTunes store is completely in the native language....
This language problems is throughout iTunes..... and in my opinion quiet annoying...
Are you with me now?
If you're referring to the iTunes Store, then in most countries there is no choice of language available. You get only the language native to the country. See the section titled "iTunes Store available languages table" on this web page: