Fricative consonants are produced by turbulent jets of air

Evidence

Fricatives are nonpitched noises that may be voiced (involving added vocal fold vibration) such as “th” in the, or may be unvoiced, such as such as “shhhhh …” or “sh” in should. They are produced by turbulent jets of air entering a region of still air, generated in many ways by tongue, lips, palate, and teeth. — Eric J. Heller, Why You Hear What You Hear- An…, 1344

Categorization

• DEFINE: Defines fricative consonants and their acoustic production mechanism in one compact statement.
• XREF: connects to: Turbulent airflow produces the nonpitched noise sounds of speech like sh and ss. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1140