Lords of Light!
In its simplest form, the Marques are tattoos that describe the important events in the individual’s life. Some of the first markings are about how conception took place, when and where the birth happened, or a infant’s first (words, haircut, time to crawl, time to walk, et al.). From them, the important events are recorded upon the flesh as a way to memorialize them. Usually, these markings start either on the back or chest.
Started by the Dark cultures (such as the Drow), these became a way to symbolize how far the individual had risen or fallen. How one improved his or her life and the overcoming of challenges. Chances for advancement are plentiful in Dark societies if one knows where to look.
In the Light cultures, social mobility is stifled if not outright banned. One’s place is determined by one’s parents, and there is little to no mechanism for change. As such, if one started as the child of criminals, one is a criminal (unless given up for adoption to become a servant or priest).
The is no “common” language to the maps, nor is there a racial language. In a few places there are “regional,” “tribal,” or “family” languages, but just as often, the languages employed are started by one or both parents and then individualized.
The Marques have their origins in the legends of Dwarves. As the Dwarves struggled to win their freedom from the Giants, they put markings upon their flesh. At first they were random symbols, but quickly the symbols took on meaning for the survivors of particular encounters with the Giants. These symbols became the basis of the Dwarven languages. And to this day, Dwarves are know to mark their skin to signify any amount of time they spend beneath the surface, any time they spend in the realm of the Giants.
Other races who failed to escape the underground and slavery still use the marques as reminders of what they need to overcome. The surface races see the marks as chronologies or journals for the individual. In many Light cultures, the marques can be used as evidence to support the arrest and punishment for upward mobility crimes.