[Please note: I am not a linguist. This is just me wanting to expand the world building even further in more interesting ways, as I love learning about languages and want to incorporate them into OFND!]
Languages commonly found within (or around) the fortress valley:
Bay — A verbal language unique to the High Water Howlers
Beakspeak — The common tongue of avians
Canid - The common tongue of canines
Common — A mix between Felid and Ruin Rasp; the primary language of the Fourtrees Fealty’s feline occupants
Felid — The common tongue of felines
Freshwater — A nonverbal signed language unique to the Riverwardens, shared with the High Water Howlers
Gesture — A nonverbal, universal signed language for Deaf cats and cats who are unable to speak. Spoken commonly within the Fenland
Groan-and-Squeak — The common tongue of rodents
(Ruin) Rasp — A spoken language most commonly spoken within ruins; it relies heavily on both body language and verbal inclinations. Every animal is able to speak it, and as such, it is rather simple
Trill — A whistled language unique to the Moorsweepers