Mutes are those consonants that are pronounced with a stoppage of the breath. Some have no vocalization at all, e.g., the breathed consonants π, τ, and κ. Others, β, δ, and γ, are voiced. Still, there is that stoppage. Early on, the rough mutes were aspirates, apparently pronounced as a combination of a stopped consonant and an “h” sound. Although it is thought that the sound of these rough mutes softened in Hellenistic Greek, they are still categorized among the mutes. The following matrix shows the categorization of mutes into three classes and three orders.
* Also called dental mutes
** Also called guttural mutes