(Info about the immersion course in Rome: http://www.pusc.it/centri/dipartimento-di-lingue/corsi-greco)
Accents were devised around the 3rd century B.C. by Aristophanes of Byzantium when Koine Greek was becoming widespread after Alexander’s conquests, to help people pronounce Greek properly, since so many people were then speaking it for whom it was not a native language. Or so I’ve read. I’ve wondered ever since learning that just what the primary sources are that support it.
So the classical writers would not have used the diacritical marks–they didn’t punctuate or put spaces between words, either, and they wrote in capitals only–but Hellenistic writers, including the Christians–would or could supposedly have used these marks.
(From another thread) Mike Bond said:
Ancient Greek should have the following “accents”: Doric, Aeolic, Ionic, Attic.
Modern Greek should have (at least) Demotic (“popular” Greek) and Katharevousa (from Wikipedia: “a semi-artificial sociolect promoted in the 19th century at the foundation of the modern Greek state, as a compromise between Classical Greek and modern Demotic. It was the official language of modern Greece until 1976”)."
Yes, I guess the optimum would be to have two slots: a) Modern Greek (Demotiki+Katherevousa); (b) Ancient Greek (Homeric, Attic, et al, PLUS Koine!)
(Nowadays Koine is by far the most widely taught form of Ancient Greek, I believe…)
But are we pushing our luck by asking for this much, I wonder…? :-0
Jay, I had copied and pasted that from THIS thread! 
Really!? Oops! 
Oh well, now it’s right back where it belongs, I guess! 
You guys have mentioned Greek diacritics working in the Dutch slot, but not in the Japanese slot. If we are importing new scripts, do we need to check them in every slot to rule them out? Which slots differ in this regard?
All slots work the same way except for Chinese and Japanese. I would not recommend using different languages in these slots.
I would totally dig modern Greek. It’s a language I want to learn more of and it would be great to have it on this site.
I would start to use Ancient Greek if it became available. Thanks for considering it.