Hi! I have been using the forums for a couple of months now and I have come across with some questions that are not in English or that have been written in English by someone who's proffered language would be other.
Whilst I find the forums an incredible helpful place, I also believe that they are very "English Focused". Therefore, I believe that by implementing very small actions you could make the forums a much more welcoming place for people who is not very comfortable writing in English.
1- I think would be cool to have small flag icons next to your avatar with your preferred languages. This way you would recognize instantly if someone would prefer to get an answer in a different language.
2- It would be good to add a tag to your posts with your preferred languages. This would allow you to filter by language, making it easier for the people who is answering questions in the forum to search if there are unanswered questions in their language.
3- I would also add sub-spaces in the forums by Language, despite the individual country User Groups. I think for a non-English speaker is a bit disappointing if you go to Página de destino de la comunidad | Tableau Software (community website of Tableau in Spanish) and you click on "Explorar la comunidad de Tableau" (explore the Tableau Community) and you are directed to a page that is fully in English.
Tableau is a software that is being used in every continent now and that aims to help people understand their data. I believe one key step to achieve this goal is to be able to communicate despite your English knowledge.