Brian Palmer in Slate.
Was Jesus a common name back when he was alive?
… The long version of the name, Yehoshua, appears another few hundred times, referring most notably to the legendary conqueror of Jericho (and the second most famous bearer of the name). So why do we call the Hebrew hero of Jericho Joshua and the Christian Messiah Jesus? Because the New Testament was originally written in Greek, not Hebrew or Aramaic. Greeks did not use the sound sh, so the evangelists substituted an S sound. Then, to make it a masculine name, they added another S sound at the end. The earliest written version of the name Jesus is Romanized today as Iesous. (Thus the crucifix inscription INRI: “Iesus Nazarenus Rex Iudaeorum,” or “Jesus of Nazareth, King of the Jews.”)
The initial J didn’t come until much later. That sound was foreign to Aramaic, Hebrew, Greek, and Latin. Not even English distinguished J from I until the mid-17th century. Thus, the 1611 King James Bible refers to Jesus as “Iesus” and his father as “Ioseph.” The current spelling likely came from Switzerland, where J sounds more like the English Y. When English Protestants fled to Switzerland during the reign of the Catholic Queen Mary I, they drafted the Geneva Bible and used the Swiss spelling. Translators in England adopted the Geneva spelling by 1769. …
The word “Jesus Christ” is just word-play. It came from “Jesu Schrift”. Which means Jewish Script. They took the “S” off of the word Schrift and made it Chrift. They added that letter to the end of Jesu to make it Jesus. Then, they modified the closely related “F” to an “S”. So, there you have it. The “Stories of Jesus”, are just that. Stories based on truth