You have to use a language pack.
Unfortunately, I don't remember exactly how to do it, and usually have to play with the site to find the location of the updates.
You do have to be the site Admin to make the change. Other than that, I believe it was just a couple of clicks.
Hope this helps.
You can simply install the American English language pack (en_us) then choose it as the default language for the site. (Source: Enrollment FAQ)
Thanks for your help everyone! It's works beautifully now.
Well, until the next glitch I find. 0 : >