Runic is the ancient written alphabet of Old Sosaria. It is phonetically similar to the English alphabet with letters from the Futhorc runic alphabet. It can be translated by simple letter substitution.
When Lord Eggleton first arrived in Old Sosaria he was surprised to find that the locals spoke a dialect of Old English but their written language was a Runic alphabet that was similar to [Futhorc]. After a brief study, he was able to read much of the signage and books in this new world by simply substituting the Runic letters for English letters.
Over time, New Sosaria has adopted the English alphabet and uses it extensively in place of the old Runic Alphabet. However you will still find references to the Runic alphabet in your travels; old signs, crumbling ruins, ancient temples - many of which still bear Runic markings.
Mages, being an elitist and aloof bunch, still cling to the Runic alphabet for their systems of magic, probably as a means of keeping their magic formulae out of the hands of the common folk. You will still find scribes selling Spell Tomes that are written in runic.
How to read Runic
The following chart shows all of the Runic letters and their English equivalents. Note that some of the Runic letters represent multiple English letters: