For "Olga Bernice" and your question on the "secret language": I have gone back and (somewhat quickly) researched what now comprehensively appears to be the EARLIEST appearance of the so-called (invented) language name "Tarabar" on this Forum.
In the thread," The Imperial children's sad,sheltered life?", Post # 93, Dec. 7, 2005," "Sarushka" says: "Slightly off-topic: does anybody know anything about the secret language Anastasia & Alexei invented? I've got the name of it written down somewhere...."
On the same day, in Post #96, December 7, 2005, she responds to a question from "Olga Anna" as follows: "Anastasia & Alexei called their language 'Tarabar.' Unfortunately my notes don't say where I read this. I can promise that it was a non-fiction source though!" This then is followed (same thread) by Post #153, Jan. 31, 2006, in which "Tsarina Liz" shows the relevant quote from # 96 and comments on it.
To my knowledge, "Tarabar" is next mentioned by name in Post # 718 of the thread, "Re: Just to put this out there.....Romanov Style" by poster "Holly": "It was called Tarabar." In response to another poster's comments, the poster,"Holly," on Jan. 17, 2011, replies in Post # 720: " I've only seen it in one book that I can remember." The only extant written example (able to be quoted from the source) followed in the same posting, #720. (Unfortunately, a follow-up on the book's name was apparently never remembered and posted.)
Therefore, in response to your question (August 8, 2011) of written versus spoken "Tarabar", only a single written alleged example has been posted on the Forum, to my knowledge. Potentially, the 2 (or 3) youngest siblings would resort (on appropriate occasions) to a spoken version, but IMO it would have been very brief in nature. Still, we have no authoritatively documented source with which to refer. It would seem to be perhaps traceable to a single reference/source?
Regards, AP.