Dear Rafaella,
welcome (again) to the project!
I'll pass on the information you provided to add Tibetan to OOo and let you know in case we need other details.
Thanks you very much for that. BTW: do you plan to have the GUI translated by the 2.3 release? Because most Tibetan speakers I know are teachers and students of Tibet University, I have to decide which release our localization will start from after I discuss with them. I will try my best to start that work early. Regards, Jia Yanmin