Like most Greek students, I started off pronouncing Greek in the standard, Erasmian pronunciation. This scheme has been used by westerners studying Greek since the Renaissance, and, with some variations, emulates the proposals put forth by the great humanist Erasmus.
Somewhere along the way, I got interested in a more authentic pronunciation scheme. Since my main interest at that time was the New Testament, I read Randall Buth’s article on “Imperial Koiné” pronunciation with great interest, which can be found here.
Among the changes that had taken place by the NT period was the merging of the οι sound and υ sound. Erasmian pronounces οι like the oi in oil, and υ was originally like the German ü, or the french u in “tu.” But in the koiné, οι and υ and both were pronounced like ü. This has already been well established by inscriptions, but I found evidence in a rather unexpected place: the Syriac alphabet!
Syriac, like many Semitic languages (Hebrew, Arabic, etc.), natively only includes a few vowels in its script proper. However, Syriac scribes did develop of system of vowels whereby vowels were placed over the consonants. Here are two images to illustrate a non vocalized, and then a vocalized word: 
.
In the second image, the vowels are written above the letters. This word, in fact, is Syriac word for God, “alaha.”
In the West Syriac tradition, which you see above, the vowels were based on Greek. There are two different vowels in the second picture above, one is a short ‘a’ (the furthest right), and the other two are long ‘a.’ If you tilt them on their side, you can make out how they resemble an alpha. The long ‘a’ appears to resemble a minuscule alpha, while the short ‘a’ resemble a majuscule one.
Syriac has a long and short ‘e’ as well, and you can see them in the following words for ‘this’ (f.) and ‘Christ’:
(hode)
(msheeho)
The short ‘e’, visible in the shorter word above, resembles a majuscule ε if my memory serves, while the long ‘e’ a majuscule η. As always, you just have to rotate them a little bit.
The ‘o’ is a bit different, in that it is actually represented in the script proper, and a small dot is simply placed above the letter to indicate it should be read as a vowel. The ‘u’ though, I found puzzling at first. For example, here’s the word that means ‘Syriac’:
(Suryaya).
The ‘u’ is the right most in the word. Once my teacher wrote a few of the alternate forms on the board, it dawned on me that this was essentially the Greek pair οι. Rather than using something based on the original Greek vowel to make this sound υ (upsilon), they used οι (omicron iota), which by that time had long merged with υ. I suppose that’s not terribly surprising, considering οι is more common than υ in Greek. At any rate, it’s another small bit of evidence to demonstrate Greek pronunciation in the postclassical period.
ἐν αὐτῷ,
ΜΑΘΠ
Alex Poulos, PhD 