The name, Yahshua
Did you know that if you could go back to the time of the twelve apostles, if you walked up to Peter and said, "Please, take me to see Jesus Christ", Peter would get a puzzled look on his face and say the equivalent of, "Who, or what is that?" Did you know that no one who followed Jesus was capable of accurately pronouncing in English the name "Jesus"? The truth is, if you could go back in time, Peter would probably say something more like, "Come, let me introduce you to Y'shua the Messiah."
When the angel Gabriel came to Mary and told her she was going to have a son and what the child's name was to be, (Luke 1:31) the sound of the name that Mary heard come from Gabriel's lips was very close to, if not exactly... "Yahushua" pronounced Yah-hoo-shoo'-ah. In modern Hebrew script, "Yahushua" looks like and is read from right to left. This name is the blending of two Hebrew words. The first part, "Yah-ho", is part of God's name that is sometimes used at the beginning or end of a Hebrew name. God's full name is likely pronounced "Yah-weh". More on this in a moment. The second part of the Messiah's name, "shua", is the Hebrew word for deliverance meaning, "saves". The name "Yahushua" literally means Yahweh/God-saves. The name Yahushua was then shortened for everyday use the same way a name like Barbara is often shortened to Barb (see the name parable), and the four syllable name Yahushua was shortened to three syllables, Yahshua. And in every day usage of the name, it came out even shorter and sounded like Y'shua.
Today, to make Y'shua more English user-friendly, some Messianics have replaced the apostrophe with the letter "e" as a least pronounced vowel in the English language, rendering it as Yeshua. This version of the Messiah's name is one that I used for some time as well. But because the "e" is almost always over-pronounced, sounding like one is beginning to say the word "yes", and the emphasis wrongly placed on the second syllable, I now prefer to use the more correctly pronounced spelling of Yahshua. It is pronounced like "Joshua" with a "y". The emphasis should remain with God's name in the first syllable.
The translation process.... Hebrew to Greek
Early on, when the Gospels were being written and the story of Yahshua the Messiah was spreading to the Gentile nations, the story had to be translated to Greek. There are two ways a Hebrew name can be brought across a language barrier. Hebrew names always carry a meaning, and one way is to translate the name, which is bringing across the meaning of the name. The other method is the most common and is called a transliteration, which is the bringing across of the sound of the name. If the translators of the Gospel story had translated Yahshua's name down through history, we might well know him as "God-saves" today because that is what his name means.
In the case of the name "Y'shua", the Greek speaking world did the best they could to transliterate his name. Usually, this involves a relatively easy process of swapping like sounding letters so a reader would end up making the same sound when pronouncing the name. In many cases this is not a problem. But in the case of the name "Y'shua" there are four problems in bringing it across to Greek. Two of them are the fact that the ancient Greek language did not contain two of the sounds found in the name Y'shua. This may come as a surprise to English speaking people, but the fact is, the ancient Greek language did not contain any "y" sound as in "yes", nor did it have a "sh" sound as in "show". The closest sound a Greek speaking person could come to making a "y" sound was by putting the two Greek letters Iota and Eta together and coming up with an "ee-ay" sound. And the closest a Greek speaking person could come to making the "sh" sound was the "s" sound made by the letter Sigma. With these two changes, "Y'shua", pronounced by a Greek speaking person would naturally come out sounding like "ee-ay-soo-ah". The third problem with transliterating "Y'shua" is the fact that traditionally, masculine Greek names never ended in a vowel sound. Those that did were generally given the letter Sigma or "s" as a suffix. This tradition was likely derived from the fact that the name of the Greek god Zeus ended with Sigma. This tradition is seen in familiar Biblical names, where Judah became Judas, Cephah (which means "rock") became Cephas, Apollo became Apollos, Barnabie became Barnabas, Matthew became Matthias and so on. So "ee-ay-soo-ah" needed to become "ee-ay-soo-ah-s". The fourth problem is that the two vowel sounds before the "s" do not flow and are virtually never seen in Greek. So the last vowel sound was dropped as it was in other names, and we were left with "ee-ay-soos". Aside from the added tradition of giving the name a masculine sound, this is the closest a Greek speaking person could come to transliterating the name Y'shua. Already by this point, the name Y'shua had lost all of it's meaning and 75% of its sound. The last vestige of it's sound was found in the "oo" (as in "soon") sound. Yahshua was known as "ee-ay-soos" to the Greek speaking world for nearly 400 years. In Greek script, "ee-ay-soos" looks like , and like English, it is read from left to right.
http://www.judaismvschristianity.com/how_the_name.htm