There is a difference between Christianity and American Christian culture. In the eastern Orthodox they have words like Theotokos, Prokeimenon and Vespers.
And yes, phrases like Pretrib Postmillennialist mean something to us, in the same way that "13-34 first strike flying" means something to someone else or "Pulling Wham block" or "Feeding the Shaft Seals" mean something to other people.
But I don't want to be in the club. I don't want to wear the tight V-neck "Not of this World" t-shirt. I don't want to speak of sanctification over my Iced double non-fat Latte, that I bought inside my church.
I want to use the language of men, to speak to men. Otherwise we wind up sounding like the Pod'Lair and no one is going to take us seriously. That is the problem with having an inside language.
Pod'Lair \| Everything is Energy Evolving <Pod'Lair, because even if they had any substance to their cult, it would be obscured in the foreign nature of their language. (Which is still English btw, well sort of)