Which page is loading in Spanish exactly? A forum post? Or something before the forums on the main IW site?
If it's forums posts that are in Spanish then it's possible that your browser is translating the page into Spanish if it's the main site then it's possible that somehow you've selected a Spanish version of the site or it's glitched that way.
To test for (1) use a different browser and see what happens and to test for (2) try logging out, deleting all site cookies and browser cache and loading up the page again.