Telepathy

Telepathy is a psionic ability which most mages and psionics seem to possess. It includes the ability to transmit and receive information without recourse to speech — a very useful skill for private communication in public places.
Certain active stones, metals and crystals while worn can block incoming and outgoing telepathic "messages", should the mage wish to remain uncontactable.
In the 13th century, monarchs around the Northern Kingdoms relied on court mages sending telepathic messages between cities, as a thirty minute delivery via psionics far outlasted a four day ride for a message by horse.
==References==
de:Telepathie
pl:Telepatia