With some discussion with feos and some cooperation with Nach, I added a new wiki module for use with translations.
Firstly, to facilitate the module, and to facilitate easier keeping track of things in general, we agreed on a new translated page structure - the language token should now be at the root of the page, rather than the end. So for example "tasvideos.org/EmulatorResources/Mednafen/ES" now becomes ""tasvideos.org/ES/EmulatorResources/Mednafen". We're currently busy with moving existing translation pages over.
As for the module:
[module:listlanguages] should be used on all pages with translated versions, where it will provide links to translated pages. If placed on MovieRules, it will link to FR/MovieRules, ES/MovieRules, and so on, for any such page that exists and that is internally recognized as a language code and title (e.g. FR - Français , ES - Español, etc.)
[module:listlanguages|istranslation=true] should be used on the translated versions of the pages, where it will provide a link back to the English version and to other languages. Put it on FR/MovieRules and it will link to MovieRules as well as ES/MovieRules, etc.
If a language or a translated page doesn't show in this module when it should, contact me.
For sample usage you can look at pages like
Wiki: WelcomeToTASVideos or a
translation of it where it already has been put to use
With this, it should be much easier now to automatically link between different translations of a page, without all the manual upkeep that used to be required.