“Jehovah” is a mispronunciation of the Hebrew name of God, resulting from a confusion over what vowels were to be included when saying the name.
The Hebrew name of God is יהוה (YHWH). This was revealed to Moses by God in Exodus 6:2-3. In Hebrew, there are usually no vowels inserted and it is up to the reader to insert the vowels at the time of reading. Most scholars think the vowels in the name of God are A and E making Yahweh.
Several centuries before Jesus, Jews stopped pronouncing the name of God as it was too sacred, and they started to substitute the word Adonay (Lord) instead whenever they came across the word Yahweh. Then later editions of the Hebrew scriptures added vowel pointings to guide readers. For YHWH, the vowels for Adonai were added to remind readers to read “Adonai” and not “Yahweh”. This actually made a non-word “Yehowah”.
The Hebrew letter “W” (waw) is now pronounced more like a “V” in modern Hebrew, and so is often transliterated as a V instead of a W. The Hebrew letter “Y” (yod) is often historically transliterated as a “J” due to its pronunciation in late Latin. Consequently, we get the name “Jehovah” although that was never the original word and probably does not sound anything like the Hebrew name of God.
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