I have added the following article to the bibliography here at Greek-Language.com.
- Vit Bubenik, “The Persistence of Dialect and the Diffusion of Koine,” Studies in Greek Linguistics 29 (2009) pp. 315-324.
Bubenic traces the parallel diffusion of the Hellenistic Koine and reduction of other ancient dialects. He cites documentation from Arcadia for the decline of the local dialect and the rise of three ‘high’ Koine varieties: general Hellenistic Koine, Achaean Doric Koine, and the North-West Doric Koine. He argues that writers and speakers moved on a continuum between the ‘high’ and ‘low’ varieties of the language in an increasingly diglossic society, and explains the ‘choice’ between the high and low varieties in terms of ‘domain’ of language use.
Studies in Greek Linguistics is an online journal hosted by the Aristotle University of Thessaloniki. You can read Bubonic’s article online there.