Possible Clues:

• Language of the Eddas
• Ancient Scandinavian language
• Don's role - translating a dead language
• Londoners without new translation for medieval language
• Leif Ericson's language
• The Eddas were written in it
• Curiously, one lord's some kind of Norwegian
• Medieval Scandinavian
• Historic Scandinavian language
• Extinct Germanic language