The double month naming in late biblical books: A new clue for dating esther?

Hebrew epigraphy evidences that the Babylonian-Aramaic month names replaced the numeral names toward the end of the Second Temple period. The use of the Babylonian-Aramaic month names in the books of Nehemiah and Esther reflects the language of the Aramaic administration at the court of the Persian king, not earlier then the middle of the 5th century B.C.E. The author of Esther employs, in addition, a compound formula that combines both name types. It also occurs in two glosses in the book of Zechariah. Since in this formula the numeral names are explained by their Babylonian equivalents-and not the other way round-it must have originated in a late period in which the ordinals were already replaced by the Babylonian names. The compound formula under discussion, therefore, cannot be a clue for an early date for Esther.