User blog comment:FairyRaven/Exceeds and Earth Land Counterparts/@comment-4933386-20120820113034/@comment-5268982-20120820192346

I think that they know about it by the Dragons' Edolas Counterparts. For example, Grandeeney and Porlyusica did have some sort of communication. Maybe the same goes for the rest of them. This means that all Dragons' counterparts, or Porlyusica herself, would talk to people in Edolas about Dragons, Dragon Slayers and other Earth Land stuff.