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 peasants of the wood use crudely carved symbols to ward off wolves. They think the symbols are emblems of purity and goodness and that keeps the wolves away. The symbols work, but not for the reasons the peasants believe...
The symbols are actually arcance evil symbols which the wolves know and fear, but to which the peasants are oblivious. So how gullible are the peasants going to be when a strange horned man displaying the symbols on his shield turns up and asks for their allegiance?