The guards are allowed to talk to each other in a language that is not known to many in the star wars galaxy they are only allowed to talk to Vader and Palpatine. If you want more information you should look at the Youtube channel Lore Master Star Wars he goes in depth when talking about Star Wars Lore. Its been awhile since I looked into the Royal Guards.What is the Oath of Scilence? What lines are Temple Guards allowed to say? Can guards engage in conversation? Are there any good sources explaining stuff about temple guards?