Not every language is currently supported, as our writers are still developing the game which makes translation difficult.
...but which ones? the list on the steam is actual for EA?
I believe what the statement means to imply is that during active development, a lot is subject to change; Particularly writing and text content. Translating into other languages would need to be an ongoing process during development to accommodate any changes made underways, so that easily snowballs into a lot of extra work any time a change or correction is made. So doing most of translation work towards the very end once everything is in a more finalized state is more efficient on both logistical costs (manpower working on it, time, coordination, QA and probably more) as well as economic makes a lot of sense to me.
I couldn't tell you for sure which languages are set in stone for EA (other than English), perhaps Raze could clarify on that when ever he gets around 😊
