fricatives

Fricatives are a class of consonants produced by forcing the breath through a narrow constriction in the vocal tract, which generates turbulent airflow and audible frication. Because the constriction is not complete, the sound is continuous rather than explosive, and it tends to have energy across higher frequencies. Fricatives can be voiced or voiceless and are described by place of articulation.

Common places of articulation include labiodental (as in f and v), dental (θ and ð), alveolar (s and z), alveolo-palatal or postalveolar (ʃ and ʒ), and glottal (h). Velar fricatives, such as x in languages like Spanish and Germanic varieties, also occur in some languages. The exact set of fricatives varies by language, with many languages possessing a mix of voiceless and voiced members.

In phonology, fricatives contrast with other consonants such as stops and affricates, and with each other by place and voicing. They can participate in phonotactic patterns, undergo assimilation, and exhibit allophony in different segments or environments. Acoustic properties include a noisy spectrum with relatively diffuse energy across higher frequencies; voiceless fricatives show less voicing vibration, while voiced fricatives display a periodic waveform accompanying the noise.

Fricatives are common worldwide, found in many language families, and form a core component of the consonant inventories that differentiate words and grammatical contrasts.