Ancient Decomian language is the oldest language in Arcana, most of it already long forgotten by the people of the present. It was used by a majority of the inhabitants before Archane's birth.
It is also the language used in the Decomus Hymn (composed and performed by Sai-shou, lyrics by Houshikaze).
Ancient Decomian uses a simlar sounds from Swedish and German phonology.
Vallen stellios - See you later