As Jelena said, we managed to translate all German help pages (I did the proof reading). We did hard work for over a year with five people, all volunteering. Whyever, technically - translated help pages go offline again, as soon as the English page is edited. So it some people doing new translations and updates all the time. That would be the case for all languages. As much as I understand, the French translating team stopped after the most needed pages, because it was too much work.
I would love to have many different lanugages both for the help pages and the surface (menu etc.). It would make WikiTree stand out and attract a lot of European genealogists who already researched their family tree for many years, but don't want to join WikiTree, because they don't understand English.
But from what I understand, the problem with translating WikiTree is not only technically: we use English to work together, and if there are many WikiTreers who can't collaborate with others, WikiTree wouldn't work anymore.
For sources: we have the Italy and Spain projects that have project pages with sources listed, so that already happened :-).
https://www.wikitree.com/wiki/Space:Italian_Roots_Resources
https://www.wikitree.com/wiki/Space:Spanish_Resources
If you know good sources that are missing there, you can comment on those pages.