How different are the ancient and modern Greek languages?

I know Ancient Greek and it is easier to read Modern Greek than to speak it or understand it spoken. Even reading it is difficult, however. There has been massive grammatical restructuring of the endings on words even though the basic spelling of the root word has generally remained stable. But there is a lot of new vocabulary to deal with and a lot of words have changed their meanings over the last 2500 years. The differences in pronunciation are quite major, especially in the vowels. I cannot understand spoken Modern Greek.

I m greek and i have studied ancient greek, i dont have a degree in philology, but i understand it well. It is a different language ofcourse, but greek was a conservative language and i ve heard that classical greek is as different from modern almost as medieval english is from modern english. New Testament greek for instance is so close to modern that even uneducated greeks understand it completely. So i think the main problem would be pronouncing, not the language as such. if u could learn ancient greek but learn to pronounce it the modern way like we do in school it could be a great help for modern greek. The vocabulary has remained about 80% the same,so u would be recognising a lot of words, but there are serious grammar changes, so endings are often different, and the syntax has changed also (that is what i always found more difficult, not the grammar). I believe if u could find a way to learn ancient greek but use modern greek pronounciation to speak-read it, u would understand a great deal in Greece. It would be hard to speak it at first, but if u would hear it for a while u would make progress very fast.

so, i believe if u would learn modern greek first, it would be much easier to understand ancient greek afterwards. I m quite sure about that.

In the 19th centuary, a Greek dialect was constructed, which was a half way point between Attic Greek and Modern Greek of that time. It was called Katharevousa (the clean one). It was the official language up to 1976. It had to be studied as a separate language to be understood as the words and endings are different (because they are more archaic).

i'm greek...they are two different languages...i would be able to understand you but you wouldn't if you only spoke ancient greek...

i think you wouldn't be able to speak ancient greek,you would be able just to read...dead languages are hard to be spoken