City dialect

Each city in Sapience has its own special city dialect usable only by citizens, and only for the duration of their citizenship. This regional patois is Achaean-based but completely magical, making it obscure to non-citizens and automatically forgotten when citizenship ends. This has obvious advantages for discussing city business privately or coordinating with city members. Unlike racial languages, dialects have no written form, cannot be learned by outsiders, and is completely immune to the necklace of comprehension.