Draconic

During the Draconic Scourge, the Winged Tyrants attempted to snuff out all notions of individual culture and unity among the sapient inhabitants under their rule. They gathered every book, manuscript, scroll, and any other forms they could find to destroy them. Among scholars, this is known as the calamity of knowledge. It has made it all but impossible to determine what life was like before the Winged Tyrants came, or even when they appeared. Indeed, if not for several brave families who passed the trade of writing on from generation to generation in secret, and several brave scholars who found small stashes of writing hidden from the eyes of the Tyrants, this vital essence of culture could have been lost for all time.
The Winged Tyrants, however, did require some servants to keep track of offerings and dealings with the sapients in their service. They kept some ledgers and small bits of writing of their own, in their own language. However, this script of theirs seems to be partially magical in nature, using glyphs and symbols rather than joining letters to make words. These glyphs have strange properties that seem to connect with the magical essence in the world. They cannot be reproduced on simple parchment, as the parchment will simply burn away when the symbol is scribed. When written in chalk on slate, the slate around the glyph crumbles to dust. When painted on a surface, the paint seems to simply evaporate. The only way to reproduce the language is painstakingly chiseling it in stone. Our scholars are studying these glyphs, hoping to discover some magical secrets, but most have decided that the language is too cumbersome to be used regularly, and our linguists consider it a dead end. They have turned their focus to restoring the histories and studying the evolution of the living languages to discover common ancestors.