In October of 2015 I wrote a blog post entitled Jesus name is not יֵשֽׁוּעַ / Yéshu'a. This post explained in detail why יֵשֽׁוּעַ / Yéshu'a can not possibly be translated as "Jesus."
Recently this comment was submitted to the blog, and rather than post it as a comment it is presented here so that a detailed explanation can be given. The comment: "(1) In the Septuagint-Old Greek translation, the sixth book is Iésous, the Greek version of Yehoshua. (2) Yehoshua (Joshua), the son of Nun, is rendered as Iésous in Ecclesiasticus 46:1. And (3) the subscript to this book in 51:30 says that the book was written by Iésous ben Sira, which is the Greek rendering of Yehoshua' ben Sirach in Hebrew. Further, (4) the several mentions of Yehoshua' in Haggai (1:1, 12, 14; 2:2) and Zechariah (3:1, 3, 7, 9) are rendered Iésous in the same version. (5) So also the Aramaic form of Yehoshua' (Yeshua'), the son of Nun, in Nehemiah 8:17. (6) See further Nehemiah 8:7; 9:4; 12:1, 10, 24, 26 for other men who had the Aramaic name Yeshua. These are all rendered Iésous in the LXX-OG, not Jésouas, as you argue (there is no 'J' in Greek)."
#1 -- The book of Joshua is not found in the Septuagint.
The Septuagint is discussed in detail in the blog post "Greek or Hebrew -- which is most authentic? The "Septuagint."
The Septuagint was originally a translation only of the Torah, not of Joshua or any of the other books in the T'nach. No one knows who translated Joshua (or the other books) -- but it is well known that the quality varies from decent to horrendous. Likewise, the Greek translations were all maintained by the Christians. More and more errors crept into them causing people like Origen to state they should not be used and a new translation from the Hebrew should be requested from Jews.
#2 The name "Joshua" in the Greek translation of the book of Joshua you are calling the Septuagint is a mistranslation.
The transliteration of Y'hōshū'a should be Ιοσοα (Iosoa) or Ιοσοας (Iosoas), Ιοσαυα (Iosaua), or Ιοσα (Iosa), but the not-really Septuagint translation of יְהוֹשֻֽׁעַ / Y'hōshū'a (Joshua) is spelt Ἰησοῦς (“Iēsous”).
This is a mistranslation.
The letter “-a” (ע / 'ayin) at the end of יְהוֹשֻֽׁעַ / Y'hōshū'a (Joshua) is not represented in the Greek translation in the "not-really Septuagint."
The ע / 'ayin should be represented in a Greek translation -- because the ע / 'ayin is a part of the word’s root (Hebrew words are based on root words).
Ergo Ἰησοῦς / Iésous is a mistranslation of the name Y'hōshū'a / Joshua.
Whoever created (or changed) the translation of the name "Joshua" in the "not-really Septuagint" played fast and loose with the Hebrew.
Not only are they missing the ע 'ayin ("-a") there is another issue with the translation.
The various Hebrew names that are similar (meaning those names that begin the letters יְהוֹ־ (“Y'ho–”) in Hebrew) are all translated Ιω– (“Io–”).
But the translators did not translate יְהוֹשֻֽׁעַ / Y'hōshū'a (Joshua) with Ιω– (“Io–”).
Why is it the only name begining with יְהוֹ־ (“Y'ho–”) in Hebrew that begins Ἰη-- (“Iē") and not Ιω– (“Io–”) is
יְהוֹשֻֽׁעַ Y'hoshu'a (Joshua / Jesus) Ἰησοῦς (“Iēsous”)?
Is it possible that the translators translated the other names properly, but somehow when it came to יְהוֹשֻֽׁעַ / Y'hōshū'a (Joshua) they suddenly made a mistake?
Check for yourself.
Examine the fourteen Hebrew names in the T'nach that begin with the letters יְהוֹ־ (“Y'ho–”) in Hebrew, and then compare them to the transliterations of these names in the not really-septuagint.
Every single of those fourteen names which were translated into Greek begins with Ιω– (“Io–”) in all of cases EXCEPT for Ἰησοῦς / Iésous / יְהוֹשֻֽׁעַ Y'hoshu'a / Joshua.
יְהוֹאָחָז Y'ho'aḥaz is spelt Ιωαχας (“Ioakhas”),
יְהוֹאָשׁ Y'ho'ash is spelt Ιωας (“Ioas”),
יְהוֹזָבָד Y'hozavad is spelt Ιωζαβεδ (“Iozabed”),
יְהוֹיָכִין Y'hoyachin is spelt Ιωακιμ (“Ioakim”) [although this is actually an error],
יְהוֹיָקִים Y'hoyachin is also spelt Ιωακιμ (“Ioakim”),
יְהוֹנָדָב Y'honadav is spelt Ιωναδαβ (“Ioanadab”),
יְהוֹנָתָן Y'honatan is spelt Ιωναθαν (“Ioanathan”),
יְהוֹעַדִּין Y'ho'addin is spelt Ιωαδιν (“Ioadin”),
יְהוֹצָדָק Y'hotzadak is spelt Ιωσαδακ (“Iosadak”),
יְהוֹרָם Y'horam is spelt Ιωραμ (“Ioram”),
יְהוֹשֶֽׁבַע Y'hosheva is spelt Ιωσαβεε (“Iosabee”),
יְהוֹשַׁבְעַת Y'hoshav'at is spelt Ιωσαβεθ (“Iosabeth”), and
יְהוֹשָׁפָט Y'hoshafat is spelt Ιωσαφατ (“Iosaphat”).
All fourteen begin with יְהוֹ־ (“Y'ho–”) in Hebrew -- and all are all translated Ιω– (“Io–”).
יְהוֹשֻֽׁעַ Y'hoshu'a is spelt Ἰησοῦς (“Iēsous”).
This seems to be less an error (since the other fourteen names were translated correctly) than to have been a deliberate choice by the translator(s) to make it look as though the spelling of the transliteration of יְהוֹשֻֽׁעַ Y'hoshu'a into Greek has been altered to make it match the way יֵֽשׁוּ Yéshu (“Jesus”) is spelt in the Christian bible.
It looks like whoever translated Y'hōshū'a into the Greek doctored the translation to make it "fit" יֵֽשׁוּ Yéshu (“Jesus”) because the Greek in the translations is not the correct translation of the Hebrew into the Greek.
Why do I say it looks like a deliberate "doctoring" to influence Christian readers?
Because just as those fourteen names are translated correctly we also have examples in the T'nach of the Greek translators properly translating the letter “-a” (ע / 'ayin) at the end of יְהוֹשֻֽׁעַ / Y'hōshū'a (Joshua) -- which is not represented in the Greek translation in the "not-really Septuagint."
In B'reshit / Genesis 38:2 the name שֽׁוּעַ Shū'a is transliterated as Σαυα (Saua) in the not-really Septuagint.
In Shmuel Alef / 1 Samuel 14:49 and 31:2 a man named מַלְכִּי־שֽׁוּעַ Malki-Shū'a is translated into Greek as Μελχισα (Melkhisa).
The Greek translators got it "right" with those names, but not with "Joshua" which they seem to try to be "matching" to Jesus. . .
The transliteration of יְהוֹשֻֽׁעַ / Y'hōshū'a (Joshua) should be Ιοσοα (Iosoa) or Ιοσοας (Iosoas), Ιοσαυα (Iosaua), or Ιοσα (Iosa), but the not-really Septuagint translation of יְהוֹשֻֽׁעַ / Y'hōshū'a (Joshua) is spelt Ἰησοῦς (“Iēsous”).
Ergo Yéshua is not Jesus' Hebrew name.
The name יֵשׁוּעַ (yeSHU'a) appears in the T'nach (Jewish bible) a a name twenty-eight times and once as the name of a town in the Judean desert. For details read The Yeshua Name Game by Uri Yosef. The name יֵשׁוּ (YEshu) appears in the Babylonian Talmud on 9 occasions.
So, Jesus Hebrew name was not “Yéshu'a” (יֵשֽׁוּעַ -- a male name).
“Yéshu'a” (יֵשֽׁוּעַ -- a male name) is not Hebrew. It is Aramaic.
It is an ARAMAIC "nickname" shortened from יְהוֹשֻֽׁעַ / Y'hoshu'a / Joshua. The name Yéshu'a” (יֵשֽׁוּעַ) was only used during the Babylonian Exile (between 597- 539 B.C.E. After the Babylonian Exile ended the name was shortened even further to ; after the Return, the name יְהוֹשֻֽׁעַ / Y'hōshū'a (Joshua) started to be shortened still further to יֵשׁוּ (YEshu) which is Hebrew, not Aramaic.
No one knows what Jesus' Hebrew name might have been, and without a time machine no one will every know. Given that Jesus supposedly lived 500 years or so post-Babylonian Exile it might have been יֵשׁוּ (YEshu) -- but we simply do not know, and the Greek name found in the Christian bible makes it impossible to know what his Hebrew name really might have been.
But we simply do not know.
Do not let missionaries who are trying to somehow get back to the "Hebrew roots" of Jesus fool you with their shenanigans. The facts do not support their guess -- which seems to be based on tying Jesus to "salvation" by choosing the fake name "Yeshua" for Jesus even though the etymology of the Hebrew disproves their "name game."
As Uri Yosef once wrote: "יְשׁוּעָה is a feminine noun (meaning salvation), and יֵשׁוּעַ is a masculine proper name, and their respective pronunciations are different. In the Hebrew language, terms applied as proper names generally follow gender. Conclusion: yeshu’AH ( יְשׁוּעָה / feminine noun) means “salvation" -- a term referring to being rescued (the physical life being saved by G-d). YeSHU’a ( יֵ שׁוּעַ / masculine proper name) can not be the Hebrew name for Jesus based on the Greek name we do have for him.
The Greek name for Jesus in the not really Septuagint are in error, seemingly on purpose.