The characters probably shouldn’t know the exact stats, but I mean, some things are reasonably obvious. For example if the barbarian pc turned an enemy into mush with a single hit in the last battle, the character can assume that they’re very strong. And so on.
I mean, they seem to have basic grammar for items and people and actions (“eyes”, “walls”, “fell”), it’s possible that they only use that weird allegory reference pattern when speaking formally to strangers or whatever. It’s also possible that their language in the original version makes more sense and is more practical and it just gets mangled by the universal translator.