The multi-lang filter allows text to be expressed in one of multiple languages depending on the selected display language. However, using the multi-lang filter is cumbersome and requires a knowledge of HTML. Being a filter, it also adds processing load.
I propose that language could be added as a criterion for conditional activities (Restrict access). This way teachers could create separate resources and activities by language, writing a separate version for each language or choosing to show to a resource/activity when a specific language is chosen.
This criterion could be shown on sites that have multiple languages installed and hidden when that is not the case.
While having multiple versions of documents may cause some redundancy, I don't believe that would be more so than the case with the multi-lang filter. There may be complications in relation to grading, which should be considered.
As well as being simpler for teachers to apply, this will also hopefully allow reduced use the multi-lang filter (although it won't replace its functionality completely).