I'm really curious about this, but I do not understand it at all. Is the Doctor's real name Thetatropolousvsgholtazsr Sigmaakronosvexsithkada? I've searched and searched for this because I suspected at first that it was just a nickname of some sort, but I did hear once that his name is tough to pronounce. Do you know anything about this? I'm dying to know! Love your blog so much, thank you for all the wonderful posts! :D <3
Hi there! The Doctor’s name has never been revealed in canon, as far as I am aware. It being a secret has been a significant part of a couple different plot arcs I think. (The fall of Trenzalore arc is what comes to mind, and everything that started with River revealing to Ten in the Library that she knows his name) (Clara reads his name in a book in Journey to the Centre of the TARDIS but it is in the timeline that is not kept)
Apparently, he has been known to tell people that his given name is very hard to pronounce. I’ve never seen the long version you mention here but Theta Sigma is a nickname from Gallifrey, specifically for use in the Academy, according to the TARDIS wiki.
So, short answer: We do not know the Doctor’s real name and I don’t think we ever will. As they have mentioned in the show before, the Doctor chose their name and therefore, that is the name that really matter. (Still, it’s fun to wonder!)