How Ancient Greek Changed (Taken from "Exegetical Gems")

Quote is from Exegetical Gems from Biblical Greek by Benjamin L. Merkle:

The Greek language used during the time of the writing of the NT is known as Koine (common) Greek (300 BC–AD 330). Before this era, the Greek language is known as Classical Greek (800–500 BC) and Ionic-Attic Greek (500–300 BC). Many significant changes occurred in the transition from the Classical/Attic Greek to Koine Greek. Here are some of those changes:

•The increased use of prepositions rather than cases alone to communicate the relationship between words (e.g., Eph. 1:5, προορίσας ἡμᾶς εἰς υἱοθεσίαν διὰ Ἰησοῦ Χριστοῦ εἰς αὐτόν, κατὰ τὴν εὐδοκίαν τοῦ θελήματος αὐτοῦ, “He pre- destined us to adoption as sons through Jesus Christ to Himself, according to the kind intention of His will,” NASB), as well as a lack of precision between prepositions (e.g., διά/ἐκ [Rom. 3:30], ἐν/εἰς or περί/ὑπέρ).

•The decreased use of the optative mood (found only 68 times in the NT). Most occurrences are found in formulaic constructions such as μὴ γένοιτο (“May it never be!” NASB; used 14 times by Paul and once by Luke) and εἴη (“could be”; used 11 times by Luke and once by John).

•The spelling change of certain verbs such as first-aorist endings applied to second-aorist verbs(εἶπαν instead of εἶπον, “they said”) and omega-verb endings found on some μι verbs (ἀφίουσιν instead of ἀφιέασιν, “they allow/forgive”).

•The increase of shorter, simpler sentences and as well as the increase of coordinated clauses (parataxis).