Afraid so. Here's a letter from Anastasia to her father, 8 May, 1913:
My Darling Sweet and Dear Papa!!
I want to see you very much. I have just finished my arithmetic lesson and it seems to be not too bad. Today it is raining and very wet. I am in Tatiana's room. Tatiana and Olga are here. I try my best to get rid of worms, and Olga says I am stinking, but that is untrue. I sat digging my nose with my left hand. Olga wanted to give me a slap, but I escaped from her swinish hand. I hope you have got a good picture of Aleksei and you show it to everybody. Tatiana is as stupid as ever. I kiss you a HUNDRED times my dear darling Papa. Olga is adjusting her trousers. When you arrive I shall be meeting you at the station. Be cheerful and healthy. Squeezing fondly your hand and face. Loving you ever and everywhere from your writing daughter Anastasia. [quoted in Anastasia's Album, by Hugh Brewster.]
They may have been royal, but they could be a bit vulgar from time to time, and didn't seem to be overly uptight about saying so. :-/