The setting-specific languages I’ve defined thus far include:
Han (for this campaign, Han is the closest thing to ‘Common’, the Middle Kingdom’s language)
Yamata (for the northern Shogunate)
Agama (for the southern river-lands)
Lao (for the southeastern rainforests)
and these replace the ‘standard’ languages like Elven and Halfling in the PHB.
‘Exotic’ languages I’m carrying over include:
Abyssal, Celestial, Draconic, Deep Speech, Infernal, Primordial.
Abyssal is the language of the Cold Hells, while Infernal is the language of the Fiery Hells. Celestial is the language of devas, asuras, bodhisattvas and other dwellers of the celestial realms. Draconic is a scholarly language, presumably taught to mortals by dragons. Primordial is the language of kami and other ancient nature gods and spirits. Sylvan is replaced by one of the local standard languages, or another like Primordial. Deep Soeech is known to a few Koropokuru and Naga, but is the near-forgotten language of those who dwell underground.