I am not sure if I get your discussion right. But I think I have similar problems with the multilanguage filter and the Klaas theme. We (or rather, my colleagues) have built a theme which is based on Klaas. We have made a lot of modifications on the front page, so it is not longer the original code, I think.
But now I have problems with the multilanguage filter. In a course? It works. In the header/menu bar? It works. But it is not working in the front page description section: whoweare_description.
I haven't access to the code directly (just admin access to our moodle installation), but if you have any great guesses which are related to the code I will forward them to my colleagues.