I've been in talks with astrOtuba on Discord, who wanted to add quite a few extra languages for the sake of the Minecraft Java Edition article. While I added some of their suggestions (e.g. Occitan, Limburgish) as dialects of existing languages on that page, it appears that the below 6 would need to be added to the template in order to be feasibly added to the Minecraft page:
|Esperanto |Interslavic |Hawaiian |Somali |Nahuatl |Ido
Of those, Esperanto in particular was apparently in quite a few games (Mini Metro, Slay the Spire, and OpenRCT2, among others), while Interslavic was apparently in Secret Saga: Xamadeon Stone and Hard Minus Classic Redux. The other 4 languages can be presumed to be Minecraft-exclusive.