John 8:43: Why do ye not understand my speech? even because ye cannot hear my word.
I have met a few people who have immigrated to America and shared with me that it takes a couple years or more to begin thinking in English. It works that way when we become citizens of the Kingdom of God too. Christians seem to me to speak in what we might call another language or another dialect. The same words can have different meanings or different depths of meanings for Christians and unbelievers. While it is true that we speak many of the same words as unbelievers, the words we speak have a life in them that an unbeliever has not experienced and cannot comprehend.
John 6:63: It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they are life.
John 6:68: Then Simon Peter answered him, Lord, to whom shall we go? thou hast the words of eternal life.
Acts 5:20: Go, stand and speak in the temple to the people all the words of this life.
Every couple and every family has their private jokes. They have unique communications among themselves that must be explained to someone outside the family. When we meet Christians from anywhere in the world it doesn*t matter how badly they butcher the English language we often understand quickly that they are brothers in Christ.
I heard of an American who took up residence somewhere in Africa. He was not fluent in the language. The neighbors where he lived did not accept him. One day they heard him humming a Christian song that had been translated into their language. Smiles broke out and they accepted him. They were Christians and learned that he was a Christian simply by the joyful melody that he hummed.
There is language that can only be understood by those who have Jesus in their hearts. It is a language in which the definitions of God are understood rather than the definitions of men. It is at times a wordless language of love, joy, peace, longsuffering, gentleness, goodness, righteousness, faith, meekness and temperance. It doesn*t even need words. It is not limited by words. It is not completely defined by words. It goes infinitely beyond words. It is heart to heart communication among hearts indwelt by Jesus. It goes beyond the ear and the mind to the heart. It is a higher voltage communication.
Someone who lisps, stutters or stammers but has received Jesus can speak it and understand it. But it goes over the head of a brilliant articulate person who has not received Jesus. Sin obliterates its true definitions. It becomes garbled by the static and interference of sin. An ungrammatical person who has received Jesus can speak it and understand it perfectly. One fluent in any language who has not received Jesus has no chance to speak or understand it.
It is spiritually life-giving and life-sustaining communication. I could not speak it or understand it before I received Jesus. Now that I have received Him I am becoming somewhat fluent in it. Christians who isolate themselves from other Christians have a difficult time learning it.
Christians must not expect unbelievers to understand everything they say or do. Mature believers must not expect new believers to understand everything they say or do either. For lack of a better way to describe this communication we might call it Christianese.