I am a member of the KTH Royal Institute of Technology reference group on language issues (Språkkommittén (Links to an external site.)) and KTH wishes to have English and Swedish language content in parallel. I have tried using enhanceable_content tabs to support multiple languages in a page (see examples at Using tabs for content in three languages: Chip sandbox). It seems to work, but I expect that there is probably a better way.
Moreover, there is a problem in that if a user has selected their user interface language in their user settings, then the content in this language should appear as the "top" (i.e., visible) tab when navigating to a given page. Similar once the user selects a language by selecting a tab, it would be good if the "Next" and "Previous" buttons took the user to the relevant page and continued to show the selected language version of the page.
Are there any good examples or best practices that others have used for supporting multiple languages in parallel?