I have developed a little app to be able to change the language to my KF. This is just a reimplementation of the original locale picker from android (missed in the KF), so no root is needed.
May be this can help you:
I complained to Google about this the day 3.5.15 was released. I also started a Google code entry on this just now. Would be great if all that are concerned would head over there and star it!