Why is Jeremiah's name spelled differently in the book of Jeremiah?

Question

Jeremiah is ירמיהו and means "Whom the LORD has appointed." It appears even the LORD uses this name:

And the word of the LORD came to me, saying, “Jeremiah, what do you see?” And I said, “I see an almond branch.” (Jeremiah 1:11) [ESV]
ויהי דבר־יהוה אלי לאמר מה־אתה ראה ירמיהו ואמר מקל שקד אני ראה

This is how his name is spelled until Chapter 27:

In the beginning of the reign of Zedekiah the son of Josiah, king of Judah, this word came to Jeremiah from the LORD. (27:1)
בראשית ממלכת יהויקם בן־יאושיהו מלך יהודה היה הדבר הזה אל־ירמיה מאת יהוה לאמר

The alternate spelling continues to be used (28:5, 6, 10, 11, 12, 15; 29:1) until 29:27 when the original spelling resumes and is continued to the end. Note: this question asks which of the two is correct: What is the Hebrew name of the prophet Jeremiah—Yirmeyah or Yirmeyahu?

What is the reason and/or significance of changed spelling? The original spelling resumes after Jeremiah's letter to those who were in the first group of exiles and the alternate spelling is also used by Daniel (9:2). Does location (i.e. Babylon) contribute or have anything to do with the spelling? How might the meaning of the name change by dropping the vav?

Answer 1

Originally the ancient Hebrew pronunciation of "jeremiah" was Yirmeyahu יִרְמְיָ֖הוּ ben cHilqiyahu בֶּן־חִלְקִיָּ֑הוּ . The last letter of Yirmeyahu ( יִרְמְיָ֖הוּ ) is vav with Shuruk making an "u" sound. - During Babylonian exile, Hebrews were forced to speak Aramaic which abbreviated names like Yirmeyahu-to-Yirmeyah & Yehoshua-to-Yeshua.

How the Hebrew yod ( י ) became an English ' j ' :

The [Hebrew] Bible was originally translated into Greek. In Greek the ‘y’ basically became an ‘i’ (the Greek iota), but pronounced somewhat like a ‘y’. This later became translated into the Latin ‘i’ – which took on either a vowel sound (‘ee’) or the consonant sound ‘y’. At a point, the letter ‘j’ was introduced into Latin to represent the consonant ‘i’, yet still pronounced ‘y’. Centuries later, its pronunciation shifted to ‘j’ – and that is the sound (and spelling) which reached the English language.

(Note that the German ‘j’ is still pronounced as a ‘y’ so when Hebrew names were transliterated in German Bibles, the ‘j’ was correctly used. It’s possible those same names were borrowed for English translations.)

In a similar vein (but much shorter journey), King Shlomo became “Solomon” because Ancient Greek had no ‘sh’ sound.

Many other perfectly good Hebrew words have equally long stories behind their obfuscation into English, such as the name of the Christian Messiah. No doubt the more popular a name was, the more it came into common use and local pronunciation.

Source: https://www.aish.com/atr/J-Replacing-Y-in-Hebrew.html?mobile=yes