Hi, Curious Kitten. I remember you!
Now, what have you got up to? Reading a book like this.
I think it's safe to say that this book is silly nonsense. Jehovah is the made up name of the Old Testament God. When I say made up, I mean that they knew the Jewish consonants, but made up the vowel sounds.
Make sure you do some reality testing when reading. Is it likely that all of these people through the centuries have been in on a giant conspiracy? Wouldn't someone have talked in the last couple thousand years?
Thanks for stopping back in, Curious Kitten. I'm glad you're continuing to read, research and learn!