Good article, it helped me.
It’s not quite clear for IE7 but it is good enough.
I’d change the steps a little, like this:
1.Open Internet Explorer,
2.Click on the Tools menu,
3.Click Internet Options,
4.On the General tab, click the Languages button from the Appearance section near the bottom of the window,
5.Click Add, if you need to add a new language (or Remove if you want to remove a language),
6.Select the required language/s and click OK to add them,
7.Click OK to close the Language Preference window, then OK again to close the Internet Options window.
NOTE You may need to restart Internet Explorer to have the changes applied.