As we now live in the year 2016 its time we got a function to add multiple languages for topics, the wikipedia style would be nice to have. Some topics are worth to have in multiple languages (we only need to provide the translation).
Very much needed. But not just for forums. For any item.
For example: we should be able to list a resource and have recourse description in multiple languages. And the resource discussion in multiple languages.
Or have a media gallery item, and have comments in multiple languages. Let the Germans comment on a German comments thread and The English on an English comments thread.