Surely in the late republic the vulgar language was Koine. The identity/status issues involved seem actually quite complex — I wish I’d had a course in this. Among the native Latin speakers of the senatorial class (e.g. between Cicero and Atticus), Greek is a sign of education and an occasional tool for adding spice to his prose — but it’s always marked as such. The primary language of their correspondence, and surely their conversation, was Latin. There must be a nationalist element at play, particularly in the city of Rome — Cicero writes about translating Greek speeches into Latin to improve his rhetoric and enrich the rhetorical arsenal of the Latin language itself. Not to mention all that Ellen Millender gyne/graece-phobic anxiety. Meanwhile everyone in the post-Alexandrian world uses Koine for commerce. And yet there’s a vulgar Latin as well, as you say. Later, we have a Roman emperor writing Meditations in Greek while campaigning in Serbia in the second century, but eventually we get to the point where western Europe speaks Latins and eastern Europe speaks Greeks. And the Church is involved in this eventually. It’s madness.

This book looks fascinating, but I can only view selected pages. I know we had it at Reed, but I didn’t read it as much as I wish I had.