One interesting point of differentiation between Greeks and Romans which eventually was flipped on its head is this - while Greek coins before the 1st century BC didn't have too many inscriptions (except for the coins of the descendants of the diadochoi) by the latter 1st century A.D. we see a profusion of koine Greek lettering on Roman provincial issues. We have to remember that the majority of citizens in the Roman empire were Greek speaking, from Achaea and Macedon eastward through Anatolia and into Mesopotamia, the Levant (where Syriac and other Semitic languages were spoken and written). Even proclamations as late as the time of Diocletian were written in Greek. In Egypt, the native population kept their language until it evolved into Coptic whilst the inscriptions in the towns were always in Greek during the Roman period. Visiting Hermopolis Magna (the modern el-Ashmunein) the remnants of Greek inscriptions on the public buildings can still be witnessed. As the Late Roman empire evolved into the Byzantine empire keep in mind that eventually Greek outlasted Latin (always the minority language) on Byzantine coinage.