The Book of Ecclesiastes in Fausset's Bible Dictionary

The speaker so entitles himself, Hebrew: Qoheleth, Greek Ecclesiastes, "the convener of, and preacher to, assemblies," namely, church assemblies. The feminine form, and its construction once with a feminine verb (Ecclesiastes 7:27), show that divine Wisdom herself speaks through the inspired king Solomon. God had especially endowed him with this wisdom (1 Kings 3:5-14; 1 Kings 6:11-12; 1 Kings 9:1, etc.; 1 Kings 11:9-11). "The preacher taught the people (and inquirers) knowledge" in a divan assembled for the purpose (1 Kings 4:34; 1 Kings 10:2; 1 Kings 10:8; 1 Kings 10:24; 2 Chronicles 9:1; 2 Chronicles 9:7; 2 Chronicles 9:23). "Spake," thrice in 1 Kings 4:32-33, refers not to written compositions, but to addresses spoken in assemblies. Solomon's authorship is supported by Ecclesiastes 1:12; Ecclesiastes 1:16; Ecclesiastes 2:1-15; Ecclesiastes 12:9. But in the book are found words: (1) rarely employed in the earlier, frequently in the later books of Scripture. (2) Words never found in Hebrew writings until the Babylonian captivity; as zimaan, "set time," for moed; Ecclesiastes 3:1, namely, in Nehemiah 2:6; Esther 9:27; Esther 9:31. So pithgam, "sentence" (Ecclesiastes 8:11); "thought," madang; 'illuw "though" (Ecclesiastes 6:6); bikeen, "so" (Ecclesiastes 8:10): thus, Esther approximates most to Ecclesiastes in idioms. (3) Words not found in the late Hebrew, but only in the Aramaic sections of Daniel and Ezra: yithron, "profit "; compare yuthran in the Aramaic targums; kibaar, "already," "long ago"; taaqam, "make straight" (Ecclesiastes 1:15; Ecclesiastes 7:13; Daniel 4:33) (Daniel 4:36 "established"); ruwth, "desire," found also in the Aramaic parts of Ezra. (4) The grammatical constructions agree with the transition period from Hebrew to Aramaic; frequent participles, the uses of the relative, Vav ( ? ) or waw- conversive rare. Probably, since the book...

Link: https://bible-history.com/faussets/E/Ecclesiastes,+the+book+of/