new skill-braile
basically you can use this to read in the dark by using little bumps on/in thick paper
niot sure if it would be used in meadeival times but it's worth a try.(at least by the magi/wizards)
Braille came half a millenia later, but there may very well have been some theoretical previous system used, though more likely in the form of a "secret text" alphabet. Or someone might have come up with something like the South American knots alphabet(based on tying special knots on strings to get messages).
So, while Braille is a total no go, something more or less like it is at least possible even if it is not very plausible.
thanks.
I think basically this would count as one of the alphabet you can read under the Artes Liberales skill. As mentioned, braille itself came far later (1829 for the braille system, 1808 for the first system by Barbier), but the medieval world was no stranger to the idea of creating new alphabet, so why not ?
Of course, someone is going to have to invent it first.
The covenant of Hedyosmos in Thebes has a form of tactile sign language by which the covenfolk communicate, because most of the covenant is bound in complete darkness. I wouldn't be surprised if there isn't some written form carved into the walls so that covenfolk know where they are should they become confused.
Mark
I am running a game and used Hedyosmos, and yes, yes they did, 
They even had the occasional tactile graffiti done by apprentices and disgruntle turbs. 
(in imagining this, one of my favorite covenants, I imagined how people would continue to be their normal selves but in this bizarre environment... fascinated me for days.)
Could spells be recorded in a braile-type system?
I'd say that with Artes Liberales, some Languages and Intrigue you can make system to record and code/decode things.