His argument seems to be that the Hebrew is characteristic of a much later era, with substantial Aramaic influence.On the other hand, a long tradition asserts Solomonic authorship, and some modern commentaries object to Delitzsch’s conclusions.
Linguistic evidence and the dating of qoheleth dating handicapped man
Aramaic became the and some Psalms, was attributed to Solomon because of the wise sayings it contains, hardly a secure basis for an attribution. Certain plural endings are also what one would expect from an exilic or post-exilic work.
In fact, some plural suffixes (eg for feminine antecedents) are consistent with Late Biblical Hebrew and Mishnaic Hebrew.
Horse's mouth: "Hugo Grotius (1644) is the first who, like Luther, rejects its Solomonic authorship, erroneously supposing, with him, that it is a collection of diverse sayings of the wise, περὶ τῆς εὐδαιμονίας; but on one point he excellently hits the nail on the head: Argumentum ejus rei habeo multa vocabula, quae non alibi quam in Daniele, Esdra et Chaldaeis interpretibus reperias. If the Book of Koheleth were of old Solomonic origin, then there is no history of the Hebrew language." C. Seow, "Linguistic Evidence and the Dating of Qohelet", Journal of Biblical Literature 115 (1996): 643-666. Conclusion: "The language of the book of Qohelet clearly belongs to the postexilic period" (p. (Seow authored the Anchor Bible commentary on Ecclesiastes.) is one of the latest, if nor the latest, of the books of the Old Testament, as indicated above all by the language in which it is written, which, though unique in various ways, has close affinities with post-biblical Hebrew.
The was written much earlier, when the consensus is that it was written later than these other books.
The book also demonstrates Aramaic influence, whether because it was originally written in that language and then translated into Hebrew, or because the author was more comfortable with the Aramaic language.
Since Aramaic developed as a separate language well into the first millennium BCE, the Book of Ecclesiastes could not have been authored by Solomon. Seow says in his paper, 'Linguistic Evidence and the Dating of Qohelet', published in the Journal of Biblical Literature, Vol 115, No 4, 1996, page 645, says the text as we have it shows full use of vowel letters, and the ample use of internal letters points to an exilic or post-exilic date.The starting point for this challenge was the publication of a volume Y oung edited with— in the words of one reviewer— the 'yawn- invoking title' of Biblical Hebrew: Studies in Chronology and Typology (2003).We currently have a two volume blockbuster in press with the title Linguistic D ating of Biblical Texts.The JBL paper David linked above actually has way more of that than I can even absorb, but not everybody’s going to be able to access that, and here we are on [email protected] It was not clear from the question how much detail you needed, in fact I read the last sentence as pointing to a general answer.I looked up the article that David cited and gave some more detail.