A. Debrunner’s scientific contributions

... complex nature of correlating synchronic and diachronic data with influences from other dialects, we are faced with difficulties relating to the development and behavior of the Greek language over the centuries. The first dialectologists drew up a list of linguistic features that characterize the different dialectal varieties of Ancient Greece (cf. Buck 1910). The fact that so many local dialects which were geographically so much distant from each other shared these features ought to demonstrate that all of them derive from the same linguistic common ancestor (→ Proto-Greek and Common Greek). This view of the facts, however , has changed substantially in recent years. The existence of a sin ...

Reference:

Encyclopedia of Ancient Greek Language and Linguistics (3 vols)