Android - What about Android App Bundles' language support?
According to a Google I/O '18 talk Google Play will download all "typically used languages" and retrieve others on demand.
In the rare case, where a user switches to a new language that we weren't aware of before, Play will dynamically deliver relevant splits to their device. (https://youtu.be/0raqVydJmNE?t=13m9s)