Stops (or mutes). Stopped consonants are so called because in sounding them the breath passage is for a moment completely closed. The stops are divided into three classes (according to the part of the mouth chiefly active in sounding them) and into three orders (according to the degree of force in the expiratory effort).
| Classes | |||
| Labial (lip sounds) | π | β | φ |
| Dental (teeth sounds) | τ | δ | θ |
| Palatal (palate sounds) | κ | γ | χ |
| Orders | |||
| Smooth | π | τ | κ |
| Middle | β | δ | γ |
| Rough | φ | θ | χ |
a. The dentals are sometimes called linguals. The rough stops are also called aspirates (lit. breathed sounds) because they were sounded with a strong emission of breath (26). The smooth stops are thus distinguished from the rough stops by the absence of breathing. ( (h) is also an aspirate. The middle stops owe their name to their position in the above grouping, which is that of the Greek grammarians.