A recent discussion about this book came up on B-Greek: http://www-test.ibiblio.org/bgreek/foru ... ie+attisch
It's precisely this sort of phrase that constitutes the bulk of the Johannides Sprechen Sie Attisch? chat book; the objection raised against that has been that these are Attic, not Koine expressions. I think the same would apply to the Platonic conversational phases. Of course I personally think that the objections are a sort of reverse-snobbery: Phrynicus warns would-be speakers of good Greek to avoid colloquial Koine usages and to adhere to "pure" Attic expressions. I think, on the other hand, that the objections to Attic conversational usage constitute a preference for the language of the street and a rejection of phraseology that Plutarch and Josephus and Philo might have used if they'd had the opportunity to chat with each other. The fact is that there were, even in the Hellenistic era, Stilhöhen comparable to the modern distinction between Katharevousa and Dimotiki
Carl W. Conrad
Department of Classics, Washington University (Retired)