Hey, thanks very much for the kind words and for sticking with the game for so long! :) I'm really glad you're enjoying it, and I hope you continue to enjoy everything I have planned for CK's future (and the sequels?)
Also, thanks for the report - always helpful to have people mention errors and such. "Quieten" is actually a word, though, and means "to make or become quiet and calm." Basically Jessica is telling them to quiet and calm down in slightly fancy language. Also, just as a matter of linguistic interest, "quieten" was originally the verb form of "quiet" although these days they're used synonymously :)