Hello
here are the languages supported for the project documentation.
Here are the languages supported in Weblate.
If one sorts the Weblate translations by translation advancement, some intriguing discrepancies between what's in Weblate and ReadTheDocs appear.
The most glaring one is the absence of Indonesian, translated at 93% currently, compared with the presence of Romanian, translated at 1%
Indonesian language is spoken by about 10 times more people than Romanian.
I think that including Chinese and Spanish despite their low translation advancement makes sense because of the huge number of people speaking these languages.
Edit: double checking my post, removed the claim about Russian, German and Italian that are included in the ReadTheDocs site.