All of the fantasy creatures of Azuria still speak the ancient tongue of our ancestors, Àrzɐrŷḁn (Az-uri-an). The only way I know to describe it is as the romances languages, old latin and gaelic all mixed together.
School children are expected to learn this from an early age, as the fairies, dwarfs, unicorns and other mystical creatures of Azuria still use this as their main form of communication. Many sects throughout the kingdom have their own what you might call ‘accents’, that add a bit of confusion to oral comprehension.
The Càarta Àrzɐrŷḁ, the “Azurian Charter”, is scribed in old Àrzɐrŷḁn. We use the old language in weddings, naming ceremonies and other official events.