Originally Posted by Starbuck_II
Whoa, why does Thieve's Cant require a literate/civilized society?
Because, as I understand it, it's a language with both a written and oral components. An Orc tribe living on the caldera of some volcano might not even use pictograms, but somehow their Rogues can read and decode hidden messages in Thieve's Cant.
Still, it's a somewhat weak objection; unless you're a 3.5 Barbarian, everyone in D&D is assumed to be literate.
My main objection is that it makes perfect sense... for the Thief class. Rogue is intentionally vague; unlike how Magic User became the much more specific Wizard, Thief was made to be more widely applicable on purpose editions ago. There really doesn't seem to be a good reason to backslide now.