One of the smallest power costs (10 pts) is Warden of the Stair. And tucked into the many abilities of the Warden of the Stair is exegesis, the ability to understand anyone within a gossamer world if you have entered the world through the Door.
You can also buy exegesis as a seperate power, see the Long Walk rule book for various power breakdowns.
Exegesis is amazingly powerful, worth the 10pts all by itself, and presents a range of narrative texture decisions for the GM to explain to players. I have to recommend GMs encourage all Players to get the power exegesis whether in the Warden package or through spending separate points. I’ll note some things here (and thanks to the LoGaS group on FaceBook for the content copy):
Does Exegesis convey meanings of words that are technical? For instance, if a character says “aortic aneurysm”, “capitalism”, “specular reflection”, or “Umbra”, would the meaning of the word or term be conveyed?
A practical way to look at exegesis (GM side if you will) is that cultural meaning is conveyed. As long as the your own culture has an equivalent for what the other person is saying, you get a meaning.
But if their world doesn’t have magic, there may be no word for it for them to get.
Two Wardens speaking together may easily overcome this effect, but Warden speaking to Fred Flintstone may have to keep the conversation basic.
Exegesis includes the meaning, but in extreme cases, you may not be passing the meaning you THINK you are. If the Warden says, “We’ve a solution to your problem but it will involve calling up Umbra.” The native speaker may hear, “We’ve brought an answer. We will pray to the Gods and get help from Pan.”
If that’s the gist of the conversation (maybe there is an immediate lack of time to make detailed response) I don’t think the GM needs to explain anything more. And if results later are complicated by the fact the natives think you are a priest of Pan, well there you are.
So at a finer level of conversation, is “Umbra” just “force of entropy”? Is the pervasiveness and universality of concept conveyed? Can you convey to natives that your team represents “Eidolon” so you can trust us?
No, I don’t think so. I think the GM can make a short list of trans-Infinite culture terms if she/he likes, but I doubt Umbra/Eidolon/Sorcery/Invocation are on that list. I’d rule the powers in the rules are not often ‘commonly known’.
If you say, ‘I have magic!’ or ‘I will solve it with science!’, you’ll mostly be on safe ground for the common language. And this quite depends on the gossamer world where you are standing. In Shatterlight, the Grand Stair is a more commonly known abstraction and discussions about esoteric matters are more commonly understood.
Talk to your GM in session zero before the game starts about the baseline of such powers in play.