Elsa's and Anna's mother's diary is written in Nordic Runes.
Georgina Haig (Elsa) previously starred in Fringe (2008) as a daughter separated from her hero parents by science that froze them in time while she was forced to grow up alone until she was able to get them free once she was an adult nearly their age. Her father was also from a different world. And while time travel is what brought Elsa to Storybrooke, time travel is what eventually fixed the problems they faced in Fringe.