A couple I knew had twin boys. Since they had no other children, the babies grew up together while learning to speak. I was there when a counselor called to ask about the language the boys were developing. They were starting to speak a language of their own.
In the movie "Mr. Saturday Night", the comic Billy Crystal has his comic character look out at a heckler and say, "See that folks? That's what happens when cousins marry."
Serious or humorous, these are examples of what happens when churches become inbred. Not only to their doctrines, but to their language. We shouldn't need a translation guide to understand them. But over time we have terms like "Pontiff, Eucharist, genuflect, and denominational myths of church origins.
I'll speak of Baptists, since I love them and know about them. I remember my grandmother saying that the first Baptist was "John the Baptist", though there was no church until after John died, and no Baptists until after Luther. Must we speak in "church speech" concerning our faiths? We invent words and doctrines found nowhere in the Bible and even contrary to it.
Confucius was asked what he would do if he were emperor. He said, "The first thing I would do is purify the language." No wonder he is considered a wise man.