Marti Matulis (a recurrent cast member playing George and other demons) appears here without prosthetics as one of the monks, Brother Paul.
When Kristen writes something in English for Fenna, the nun replies "No English, me Dutch." It's possible that lead actress Katja Herbers came up with this nationality for the character of Fenna as a joke, because The Netherlands is the number one country in the world when it comes to residents speaking English when it's not the main language. More than 70% of all Dutch people speak English and a girl moving to the United States would be fluent. Katja Herbers would know this, being Dutch herself.
A largely or entirely silent episode is a longstanding tradition in television history, often seen as a creative challenge for a writing staff. Some of the best-ever examples of the genre include "The Boy From 6B" (an episode of Only Murders in the Building that is mostly executed from the point of view of a Deaf character, and therefore mostly performed in American sign language); "Rm9sbG93ZXJz" (an episode of The X-Files in which Mulder and Scully must remain mostly silent as they battle an AI run amok); and "Hush" (an episode of Buffy the Vampire Slayer in which every person in Sunnydale is silenced by floating demons who steal voices).