Turbulent airflow produces unvoiced fricative speech sounds

Evidence

Turbulent airflow is the mechanism responsible for the nonpitched sounds in speech such as the “sh” in shoe and the “ss” in sea, for which waveforms and spectra are shown in Figure 3.9. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1140

Categorization

• DEFINE: Defines laminar vs turbulent airflow as the physical distinction behind pitched vs noisy speech sounds.
• XREF: Connects to earlier chapters on sound-source mechanisms and to the reader’s broader interest in how sound mechanics produce perceptual phenomena. — connects to: Airplane engine loudness fluctuations stem from scintillation, not an unsteady pilot; Turbulent airflow produces the nonpitched noise sounds of speech like sh and ss. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1140
• corroborated: 4 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1140