This may be related to
MOBILE-2491 and probably was dependent upon MDL-58713, but we have just realized that while the mobile app itself can support multiple languages and the Moodle can support multiple language pretty seamlessly - having content in multiple languages isn't seamlessly supported.
This is particularly a challenge for places, such as Canada where content and websites might legally need to be fully available in multiple languages, but from a user experience level will be a challenge in all multilingual areas.
To help demonstrate I've attached two screenshots both showing the same course - one from a mobile browser and the other in the mobile app. In both French has been chosen as the preferred language.