Koine Greek phonology

The Greek language underwent pronunciation changes during the Koine Greek period, from about 300 BC to 300 AD. At the beginning of the period, the pronunciation was almost identical to Classical Greek, while at the end it was closer to Modern Greek.

The most significant changes during the Koine Greek period concerned vowels: these were the loss of vowel length distinction, the substitution of the Ancient Greek system of pitch accent with a stress accent system, and the monophthongization of diphthongs (except αυ and ευ). These changes seem widely attested from the 2nd century BC in Egyptian Greek, and in the early 2nd century AD in learned Attic inscriptions; it is therefore likely that they were already common in the 2nd century BC and generalized no later than the 2nd century AD.

Another change was the fricatization of the second element of diphthongs αυ and ευ. This change likely took place after the vocalic changes described above occurred. It is attested in Egyptian Greek starting from the 1st century AD, and seems to have been generalized in the late Roman period.

Another series of changes was the fricatization of voiced stops, which is widely attested in Egyptian Greek starting from the 1st century AD, but may have been generalized at a later date, possibly in the late Roman or early Byzantine periods.

Yet another series of changes was the fricatization of aspirated voiceless stops, which is attested in several locations from the 1st century AD, but seems to have been generalized at a later date, possibly in the late Roman or early Byzantine period.

A last change (possibly related to fricatization of aspirated stops) is the loss of /h/, which may have begun as soon as the late 1st century BC in Egyptian Greek, seems to have taken place no earlier than the 2nd century AD in learned Attic inscription, and had most probably been generalized by the late Roman times.

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