(1) Mutes— Smooth Middle Rough With s Labial, π β φ ψ Palatal, κ γ χ ξ Lingual, τ δ θ ζ (2) Liquids— λ, μ, ν, ρ, as in English, σ(ς) is a sibilant. (3) ζ, ξ, ψ are called double consonants. Bt. 12; Gl. 38; Gn. 18-22.