Does an Int lower than 9 impact the Read Language thief skill?
I’m kind of amused by the idea that a character would be just as likely to make sense of a dead tongue as they would their native language, but I’m not entirely certain it’s intended to work that way.
I’m not sure there are enough penalties for a low Intelligence, though. As written, there is no proficiency penalty applied to starting proficiencies.
Perhaps I’m just cruel, but I might make such a thief spend their general proficiency on Language if they didn’t want to be unable to write or have to roll each time they were called upon to read.
I would handle it as some sort of gift/reading disability where sometimes words and sentences make no sense no matter what language they were written in.