I’ve written a couple of answers where I’ve translated Classical Greek using only my knowledge of Modern Greek—although I was being overly permissive about understanding Classical grammar.
So. Daphnis & Chloe, 2.5.
Thereupon, he burst into loud laughter with a voice unlike that of a swallow or nightingale or swan. At the same time, he turned into an old man like me and said: `Philetas, it’s no trouble at all for me to kiss you, for I want to be kissed more than you want to be young again. Consider this: Is this gift good for you at your age. For old age won’t help you or keep you from chasing after me once you have had your single kiss. But I’m hard for the hawk to catch or the eagle or any faster bird, if there is one. I’m not a boy, even if I look like one, but I’m older than Cronus and all time itself. I knew you as a youthful shepherd pasturing a broad herd on that mountain over there, and I sat beside you as you were playing your pipe beside those oaks yonder when you loved Amaryllis, but you didn’t see me. Yet I stood right next to the girl. It’s a fact that I gave her to you, and now you have children, good shepherds and farmers.
Translating with only educated Modern Greek:
Here, laughing a very ??, they let off a laugh such that either a swallow nor a nightingale similar to me becoming an old man. “To me, O Philetas, it is no pain to kiss you. For I probably want to be kissed, or you would become a young man. But look if the gift is to you according to age. For old age will not benefit you towards not expelling me after one kiss. I am hard to hunt, and to a hawk and an eagle and if any other vulture sharper than them. These, I am a child and if I think a child, but even older than Cronus, and that whole year. And I ?? you distributing ?? in that mountain the broad bucolics and I was by you ?? towards those ??, because ?? of Amaryllis, but you did not ??? me though indeed next to the maiden ??. So I gave you her, and already there are children for you, good natured bucolics and farmers.
ἐνταῦθα πάνυ καπυρὸν γελάσας ἀφίησι φωνὴν οἵαν οὔτε χελιδὼν οὔτε ἀηδὼν οὔτε κύκνος ὅμοιος ἐμοὶ γέρων γενόμενος· «ἐμοὶ μέν, ὦ Φιλητᾶ, φιλῆσαί σε πόνος οὐδείς· βούλομαι γὰρ φιλεῖσθαι μᾶλλον ἢ σὺ γενέσθαι νέος. ὅρα δὲ εἴ σοι καθ᾽ ἡλικίαν τὸ δῶρον. οὐδὲν γάρ σε ὠφελήσει τὸ γῆρας πρὸς τὸ μὴ διώκειν ἐμὲ μετὰ τὸ ἓν φίλημα. δυσθήρατός εἰμι καὶ ἱέρακι καὶ ἀετῷ καὶ εἴ τις ἄλλος τούτων ὠκύτερος ὄρνις. οὔτοι παῖς ἐγὼ καὶ εἰ δοκῶ παῖς, ἀλλὰ καὶ τοῦ Κρόνου πρεσβύτερος καὶ αὐτοῦ τοῦ παντὸς χρόνου· καί σε οἶδα νέμοντα πρωθήβην ἐν ἐκείνῳ τῷ ὄρει τὸ πλατὺ βουκόλιον καὶ παρήμην σοι συρίττοντι πρὸς ταῖς φηγοῖς ἐκείναις, ἡνίκα ἤρας Ἀμαρυλλίδος, ἀλλά με οὐχ ἑώρας καίτοι πλησίον μάλα τῇ κόρῃ παρεστῶτα. σοὶ μὲν οὖν ἐκείνην ἔδωκα, καὶ ἤδη σοι παῖδες, ἀγαθοὶ βουκόλοι καὶ γεωργοί
Can they understand it? It’s not Thucydides, the vocabulary and syntax isn’t that bad. But as with other classical texts: they will miss a lot.