Nobody knows for sure how Jesus’ name was pronounced in his lifetime and more particularly in the region that he lived, because Jews in those had several different dialects and there was a strong influence of Greek as well.
Christian scholars now admit that Muslims didn’t invent the name “Eisa” and it must have existed in Syria prior to the coming of Islam. Here is a brief quote and references from this web site:
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“So far as the word ‘Isa (the name given to Jesus in the Kur’an) is concerned, it was apparently in use before Muhammad, and it does not seem probable that it was coined by him. A monastery in South Syria, near the territory of the Christian Ghassanid Arabs, bore in A.D. 571 the name ‘Isaniyah, that is to say, “of the followers of Jesus,” i.e. of the Christians. See fol. 84b of the Brit. Mus. Syr. MS. Add., 14, 602, which is of the end of the sixth, or at the latest of the beginning of the seventh century (16). The Mandean pronunciation “A’Iso” (17), is of no avail as the guttural ‘Ã© has in Mandaic the simple pronunciation of a hamzah. The Mandean pronunciation is rather reminiscent of ‘Iso, as the name of Jesus was written in the Marcionite Gospel used by the Syrians.”
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Some Western Christians are convinced that the ONLY way Jesus’ name could have been written or pronounced is Yashu’. This theory is based on the following premise: Greeks translated the name Yahushua [used in the Torah] and Yashua [used in Ezra-Nehemiah], as Iesous. Then the same word Iesous was used for Jesus by NT authors. So Jesus’ name must have been Yeshua. The problem with this theory is that because of the limitations of Greek in conveying Hebrew/Aramaic names, the only way one can write Yahushua, Yeshua, Yeshu’, Eisho, Eiso etc. is by writing Iesous. So, in my view, Greek cannot be used to firmly establish the correct pronunciation of Jesus’ name.
Jesus’ name in Aramaic-the language that he spoke-is Eisho or Eiso, which is sometimes pronounced as Eishaw.
Critics argue that even some modern Aramaic speakers now call Jesus, Yeshua. The fact is that these Aramaic speakers have been influenced by Jewish/Christian Arabs who have bought the “Greek-is-right” argument. Historically, the Aramaic name of Jesus was/is Eisho, as any Aramaic scholar would testify.
Jesus’ name in Aramaic was Eisho (YODH-SHEEN-WAW-AIN). But the way it is pronounced is very different than in Hebrew or Arabic. In this case, the YODH is pronounced as –EE not YE. In both Arabic and Hebrew, every time you have a WAW before AIN, the sound is that of -OO or -U as in Yeshu3, but in Aramaic it is -O sound and that is why AYN is silent. That is why in Aramaic, Jesus’ name is pronounced as Eisho and not Yeshu. See this web site for reference:
http://www.learnassyrian.com/aramaic/ Scroll down to example number #28 there you will find Jesus’ name written as EE-SHO MSHEE-KHAA.
There were several dialects spoken during Jesus’ time. It is very possible that people called him by different names, according to their own dialect. Some must have pronounced SHEEN as SEEN because of Greek influence which is confirmed by the fact that at that time the same letter SHEEN was used for both sounds. So people might have called him by all sorts of names: Yeshu3, Yeshu (without the AYN), Eisho, Ee-ay-sooc’, or Eisaw, depending on their dialect.
The AYN in Yeshu3 was dropped either during the time of Jesus or soon afterwards. There are various theories about that but the important one is that Yeshua means “Saved” and since according to Christian/Jewish belief, Jesus couldn’t save himself, the name was shortened to Yeshu (without the AYN), and Jews used the remaining letters yod-shin-vav as an acronym for “yemach shemo v’zikro” (“May his name and his memory be erased). But that is far fetched and most likely it was due to Aramaic rather than any insult.
As stated earlier, in northern Israel, where Jesus was born people pronounced SHEEN as SEEN. See this web site;
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“In Aramaic, Jesus’ name would have been pronounced Yesu by the Galileans (including Jesus’ Himself), and as Yeshu in soutern Israel, because they were typically able to pronounce the “sh” sound of the Hebrew letter shin, whereas northern Israelites could not (See Judges 12:5-6).
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Here is quick chart as to the history of the name:
1000 BC: –Yehushua
300-400 BC:–Yeshua (Ezra Nehemiah)
300 BC-0 BC:–YODH-SHIN-WAW-AYN (Aramaic), pronunciation in dispute but most likely same as in current Aramaic: EISHO or EISO. Was AYN pronounced? Northern Israelis pronounce SHIN as SEEN.
0 BC- 300/500 AD:–YODH-SHIN-WAW (No AYN) (Talmudic Period). Reason why AYN was omitted is in dispute.
1000 AD:–Mesorites, Hebrew makes a come back, [Return of the AYN?], Christian Arabs write “Yasu'” (with AYN at the end).
1000 AD-Present: YODH-SHIN-WAW (No AYN)…Jews still insulting Jesus by omitting AYN from his name?
Now the only issue is why Ayn appears at the beginning of the name. That could be due to metathesis, which is fairly common in Semitic languages. For example, some people whose name is “Ahmad” are called “Hamada” in Arab countries. It is also possible that since the Ayn had been dropped, even during Jesus’ time, Syrians, who were the earliest Christians put it at the beginning out of respect or were instructed by God to do so. In the Bible, for example, God changed Abram’s name to Abraham.
As you can see it’s difficult to prove what was the correct pronunciation. Quran used the name that Arabs were familiar with and the Marcionite Gospel proves that Muslims certainly did not invent the name.
One more fact that you may not be familiar with: Hebrew had died as a spoken language and was reinvented only couple of hundred years ago by the founders of Zionism who had no choice but to borrow Arabic grammar. The Hebrew previous to that was limited to the study of Torah, which only had 500 root words, insufficient for a spoken language. So the Hebrew that you hear today is not what was spoken three thousand years ago.