Thylean: This is the Common trade language of the world. Spoken by almost everyone. Language of the settler races
Giant: Cyclopes, Gygans, and other Giants. Despite dwindling numbers, the Gygan culture left a big impact on the world.
Sylvan: Fey creatures, natives to Thylea, the Titans, quite a few settlers as it is the second most common language in the world.
Uncommon Languages
Amazon: Amazonians or a descendent. A language unique to the Amazonian culture with roots in the Sylvan language.
Aquan: Underwater creatures. Roots in Primordial
Celestial: Sirens & Harpies. Celestial & Divine beings. Many Gods.
Draconic: Dragonlords and Dragons. Priests of the Five. Super devout worshippers/fans of the Dragonlords.
Infernal: Tieflings (called Stygians in this setting), Fiends from the Underworld, Practitioners of Dark Arts, and denizens of the Nether Seas.
Rarely Spoken Languages
Abyssal: Creatures from The Hollow World. Demonic beasts.
Deep Speech: A language of madness and insanity.
Druidic: Druids
Primordial: the language of elementals and elemental beings. Used in arcane studies and druidic cultures, and the Father tongue of Aquan. Popular among summoners.
You are on your own
Lost One: Any other unique racial or cultural languages brought from other realms
Undercommon: Creatures of the Underdark (Called the Hollow World) just speak Abyssal.