οι = ο + ι as Eng. oi in oil.
υι = υ + ι as Fr. ui in lui.
In ᾳ, ῃ, ῳ the first vowel was long, and the second only faintly heard.
ει. The precise sound of ει is difficult to determine, but in Attic Greek it was never confused with η till a late period, and to maintain the distinction clearly it is perhaps best for English students to pronounce it as Eng. eye, though in fact it must have been nearer to Fr. ée in passée, Eng. ey in grey. The Greek Ἀλφειός is Latin Alphēus.
αυ = au, as Germ. au in Haus, nearly as Eng. ow in gown.
ευ = eu, nearly as Eng. ew in few, u in tune.
ου as Eng. oo in moon, Fr. ou in roue.
Consonants
π, β, τ, δ, κ, and γ as p, b, t, d, k, and g respectively in Latin; except that γ (before γ, κ, and χ) is used to denote the nasal sound heard in Eng. ankle, anger.
ρ, λ, μ, ν as Lat. r, l, m, n.