Thank you! There's no in-game tool to decode the letter, but the alphabet is Ogham (primitive Irish). If you search for it online, you should be able to find several sources to help translate the Ogham script!
how do you view the letter? I picked it up for the door but can not find any way to use it now that I am at the door
Ah, perhaps a closer look at the game files might help? ;)
