User blog comment:Darknessabove/Strange World: Volume 1, Chapter 2: Recognition/@comment-135.26.27.11-20141209031102/@comment-208.66.198.210-20141212115207

Well Pb if don't like the simple "its magic" principle, then allow me to make more complex. The spell that the sage or whatever, uses the concept of a Universal translator. This would most likely involve using telepathy to put the sage's knowledge of the common language of the MGE world's inhabitants into Karl's mind, thus, giving him knowledge of the language and allowing him to speak it and understand it.