Consonant classes are produced by distinct vocal tract closure configurations

Evidence

1. Plosives /p, b, t, d, k, g/: The vocal tract and nasal tract are completely closed causing a short silence /p, t, k/, or almost completely closed causing a faint voiced sound /b, d, g/. When the tract is opened, a short impulsive sound, or burst, is generated. The impulsive sound can be either noise-like or an exponentially decaying harmonic tone complex. … 3. Trills /r/: In trills the articulator vibrates rapidly (with a frequency of about 20–25 Hz) against the place of articulation. … 4. Fricatives /f, v, T, D, s, z, S, Z, h/: The vocal tract is almost closed, because the articulator is brought close to the position of articulation. The narrow passage causes turbulant airflow, which is called frication. The frication causes a noisy sound, which is modified by the resonances of the vocal or nasal tract. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 582

Categorization

• DEFINE: Classifies the six consonant manners of articulation by how the vocal/nasal tract is configured to generate sound.
• corroborated: 2 independent passages support this claim — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 582