How then did Jews "create" the Hebrew language?
Virtually the entire Old Testament after the 5 books of Moses was written by Jews, including all of the books of the prophets. All of the later prophets: Isaiah, Jeremiah, Ezekiel, etc. were Jews.
So what does that prove? The Jews were still merely users of the Hebrew language. They did not create the language, and as far as I'm concerned they do not own it. I don't know where or when the Hebrew language began, but it was long long before there were any jews.