No worries! I will try to help as I'm able. There's a pretty good chance my code has become outdated, but let's see what we can figure out!
So according to this renpy documentation page,
renpy.change_language(language, force=False) Changes the current language to language, which can be a string or None to use the default language.
Have you changed "language" (the brackets) to the new language on that menu?