While no one in the first century would have said Merry Christmas (Kαλὰ Χριστούγεννα) because the early Church had not yet begun celebrating Christmas, if they had said it, it would have sounding like the recording above. At least that’s what the best evidence for Hellenistic Greek pronunciation suggests.
In 2019 Merry Christmas is a widely used greeting at this time of year, of course, and if you would like to deliver the message in Hellenistic Greek, I hope the recording helps. May you and your family have a beautiful Christmas this year.
Today I received notice that KoineGreek.com (Benjamin Kantor) has completed the remaining chapters of the reading of the Gospel of Mark in Koine Greek, including the addition of subtitles. This is a wonderful Christmas gift to the larger community of people learning Hellenistic Greek.
You can view the videos (chapter by chapter) at https://www.koinegreek.com/ntvideo