Make sure that the currently-set language is the one that shows on the left sidebar if no language  preference exists.

Some students were confused by the display on the sidebar when it would say 'English' even if the text was in another language. This should fix the problem.

@flowerhack @sarina @stephensanchez 

ECOM-135
Yup, this should not affect new users, just FYI, because we automatically set a language preference for them when they register. It's the older users who do not have an explicit language set in our stored user preferences who are running into confusion.