So, if a mage finds an arcane scroll written in a language he doesn’t understand, he can cast “Read Language” and use it.
If a cleric finds a divine scroll written in a language he doesn’t understand, is he just out of luck? Is there any way for him to translate it? I suppose he could take it to a more-learned cleric and work out a trade for an identical version of the scroll in a language he can read.
Some divine spellcasters might have read languages on their class list. If not, they can use a proficiency to learn the language, or, as you note, sell it/trade it.
I hadn’t thought about alternate spell lists. Good point!
Our Corruption-Cleric is still going to be out of luck, but any future Clerics of Knowledge will now have some options.