Obstruenten

Obstruenten, or obstruent consonants, are a class of consonants characterized by an obstruction of the vocal tract during production. This obstruction can be so extensive that airflow is completely stopped (as in stops), or so turbulent that it creates continuous noise (as in fricatives). A broad traditional distinction in phonetics separates obstruents from sonorants, which include vowels, nasals, liquids, and glides.

The main subtypes of obstruents are stops (plosives), fricatives, and affricates. Stops involve a complete constriction of the vocal tract followed by a release (for example p, t, k, b, d, g). Fricatives produce a narrow constriction that generates audible turbulence (for example f, s, ʃ, v, z). Affricates begin as a stop that releases into a fricative (for example t͡ʃ, d͡ʒ). Obstruents can be voiced or voiceless, and many languages also contrast aspiration in stops, as in English pʰ vs p.

In speech, obstruents tend to dominate syllabic structure and consonant inventories, often serving as the primary means of distinguishing words and grammatical forms. Their distribution and phonotactics vary across languages, influencing patterns of syllable structure, consonant clusters, and word boundaries. Additional variation includes the presence of ejectives or implosives in some languages, which are still classified as obstruents in broader typological schemes.

The term obstruent originates from Latin obstruere, meaning to obstruct, and is widely used in phonology and articulatory phonetics to group consonants by their constricted airflow, in contrast to sonorants and vowels.