How is God's name Jehovah when the letter j is only s few 100 years old?

It is 4 letter read from right to left   Hey Vav Hey Yod

so we would read Yod Hey Vav Hey,

These letters are far older than you think. . .

If you look at the letters individually you can also read

Yod…….. arm and handHey…….. behold, (man with arms and hands raised)Vav………..nail, hook, secureHey ………..behold, (man with arms and hands raised)Now who does that remind you off( behold the hand behold the nails.)

The word "Jehovah" is a transliteration from one of several Hebrew names for God:  יהוה  The Hebrew language has no letter that uses the English "j" sound, so the Hebrews used a letter called "yod" י that has a "y" sound; and when transliterated into English, somebody decided to used the letter "j".  In Hebrew, they pronounce it as "Yehovah".  

This is an oversimplified explanation, but I did not want to get into the theological reasons about why this is done, and why many Jews use the "Adonoi" name instead of "Yehovah." 

Good point.  It's a made-up name anyway.

joe -- ‘Jehovah’ is the best-known English pronunciation,”   No it's not.  I never heard of it until I saw the Indiana Jones movie and wondered who the heck he was talking about.  And I live in a big city.

joep -- According to rabbis, neither "Yahweh" nor "Jehovah" is a legitimate name.

What is the correct Name for the One we worship, Yahweh or Jehovah?

Yahweh’ is favored by most Hebrew scholars” (ibid). The fact that names are not translated but transliterated, therefore the statement, “ ‘Jehovah’ is the best-known English pronunciation,” is factually and grammatically incorrect.

“The Lord. The Hebrew for his name is Yahweh, often incorrectly spelled ‘Jehovah’”

Jehovah’s Witnesses insist that God’s name, YHWH in the ancient Hebrew manuscript copies of the Old Testament, is supposed to be pronounced “Jehovah.”

So persuaded are they about this, they believe they are the only church (organization) who has God’s favor, because they are the only ones who consistently call God by this name. Yet, Jewish and Christian scholars, who are thoroughly familiar with the Old Testament Hebrew language and how to pronounce Hebrew words, make it clear that the Hebrew word YHWH is more accurately pronounced “Yahweh” (Yaw-Way) rather than “Jehovah”.

Firstly, that isn't the name.  It's based on a mistake.  Secondly, the name is written in Hebrew script, which uses yod for that letter.  Thirdly, the letters I and J both existed but were used in different parts of a word, so J did exist and would've been used sometimes.

Here you go:

Go to the link below for an answer by a Jewish person, surname Hill, who explains the way the ancient Hebrew wording that some turn into ‘Jehovah’ cannot mean a name for God. The 4 letters of the Tetragram were about the essence of God's being. The 'Jehovah' camp would limit God by trying to restrict Him to one word, as if one word sums up who God is! In  Exodus 13-15, Moses is told "e’ye asher e’ye". E’ye and y-h-v-h share a root which means “being. ”We are speaking of the Ultimate Being! How can any one word in human language convey that?

The Being of God is too wonderful for us mere mortals to grasp. He is beyond words, but words are what He has given us to grasp what we need to know, and that it why it takes a study of the entire scriptures to grasp something of the complexity of the one Being of God. It is incredibly foolish to think that by learning one name, a person has got on intimate terms with the one who tells them his name.

This is proven in Judges 13:15-23 when Manoah asks the messenger of God what his name is. He is questioned as to why he wants to know that name, then told, “My name is wonderful” (or, “beyond understanding” or “secret” in other translations). At which point he enters the flame from the altar and ascends up to heaven. We are later told in Isaiah 9:6 that one of the ‘names’ of the Messiah is “Wonderful”. And when this Messiah comes down to Earth as the man, Jesus Christ, He takes that phrase in Exodus 3:14 and applies it to Himself (John 8:58-59). The Jews who heard Him say that were so horrified, they tried to stone Him to death for blasphemy. It certainly would have been blasphemy had it not been true. “Wonderful”, indeed! Too wonderful for mere mortals to fully grasp – this side of eternity, at any rate.

The English language is also a few hundred years old.  Jehovah is the English translation of the Name.  

Since English is derived from German and Anglo-Saxon, it is not surprising that English words are different from Hebrew words. For instance, the letters J and Y  have interchangeable sounds in German and English, as do the letters W and V.  Early elementary schoolchildren who are learning to read have to identify sounds that indicate the presence of a letter in a word.

 Jehovah was used in the English translation of the King James version, and until recently, in the Catholic versions.

The English language is extremely adoptive.  In Edwin Newman's popular series "The Story of English", he pointed out that while the English were conquerors of countries all over the world, they adopted many words of the conquered. For this reason, some English speakers say that the English language has a million words.

But the true God said about this Name, which was originally in the Scriptures:. 

15 Then God said once more to Moses:

“This is what you are to say to the Israelites, ‘Jehovah the God of your forefathers, the God of Abraham,the God of Isaac, and the God of Jacob, has sent me to you.’ This is my name forever, and this is how I am to be remembered from generation to generation." Exodus 3:15

Unlike the many titles of God, this particular Name was written in the earliest extant manuscripts about 7000 times.  This fact identifies this NAME as a unique designation of the true God.  

It is mankind that disrespects it by removing his Name from His Scriptures.  The Jewish superstition that said,  that God's Name should not be included in conversation or in any writings is against every scripture that we have, and was never adopted or approved by Jesus Christ, who commanded that Christians must preach to all nations.

That superstition developed after the completion of the Scriptures, which were inspired by the true and living God.   Before that development, the Jews of ancient times used God's Name in greeting in daily conversation.  Ruth 2:4.

 The Psalms repeatedly described that it is God's will that the people of the nations, non-Jews, also come to know, identify and praise the Name of the Most High God, as Psalm 83 made clear, especially verse 18. That Jewish superstition mentioned above contradicts God's express words.

Isaiah, chapter 12 is an invitation for people of the nations as well as the Jews to know and praise the Name of the one true God.

Billions of people know the prayer that Jesus taught his disciples in Matthew 6:9-13, but few recognize the obvious fact that in order to hallow or sanctify the name of the Father in heaven, one must know it and use it, following the example of Jesus Christ in his words at John chapter 17.

Jesus' said :

  “I have made your name manifest to the men whom you gave me out of the world. They were yours, and you gave them to me, and they have observed your word."

"I have made your name known to them and will make it known, so that the love with which you loved me may be in them and I in union with them." John 17:6,26

Jesus' is our example.  If he made his Father's name known, those to whom he made it known must also do so.

Like every other word in the Bible, it is a translation of the original texts in which the Bible was written.

The letter “j” may not be that old but the sound is from biblical times.    Take for example other ancient biblical names such as Jeremiah, Josiah, Joshua, etc.    

God doesn’t have “A” name, he has many names.