One thing holds consistent across the numerous worlds of science fiction and fantasy: everyone speaks the same language. Whether it's Lojban, English, Common, or the High Tongue of the Autumn Empire; there's one language that everyone knows, unless plot demands otherwise.
Do not gather and heap up and store for yourselves treasures on earth, where moth and rust and worm consume and destroy, and where thieves break through and steal. Matthew 6:19 KJV
The Wizard-Brewers of the Old Empire stored memories in bottles of mead, passing their brightest ideas, most subtle magics, and most important decisions on to their heirs in bottles of oddly-flavored honey-wine. A cache of these ancient magical vintages has been unearthed, but does anyone dare drink from it? The ancient mead's creator is a complete mystery, as are the thoughts he left behind.