consonant

consonant

one of the speech sounds that are combined in syllables with vowels but, unlike vowels, do not form syllabic peaks.

Acoustically, consonants possess relatively less overall energy than vowels and need not have a clear formant structure. In terms of articulation, they are characterized by the presence of a noise-producing obstruction in the epiglottal cavities of the speech organs; they are produced in a precisely determined manner and have a strictly fixed point of articulation. In addition to the noise source, a tonal sound source—the larynx—may also participate in the articulation of consonants; in the larynx, the “voice” feature is created by periodic vibrations of the vocal cords. Depending on whether only the first source or both sources are present during the articulation of a consonant, a distinction is made between voiceless consonants, such as the Russian p, t, s, and x, and voiced consonants, such as the Russian b, d, z, l, and n. The voiced consonants include a group of resonant consonants (sonants), such as l, r, m, n, and j, which are distinguished from the obstruents, both voiced and voiceless, by the presence of a clear formant structure. The clear formant structure makes sonants similar to vowels, although sonants are characterized by less overall energy. Sonants include the nasal consonants. During the articulation of nasals, the soft palate is lowered, thus causing the nasal cavity to act as a resonator.

According to the nature of the noise-producing obstruction, consonants are classed as stops, fricatives, or trills. Stops are formed by bringing together two active articulatory speech organs, such as the lower and upper lips (p, b, m), or by bringing an active organ into contact with a passive one, for example, the tongue with the palate (t, d, n, k). The stop may end either with a sudden release and explosion or a gradual release and transition to an aperture. In the first case, plosives are produced, such as p, b, t, and d, and in the second case affricates result, such as the Russian ts and tf. Affricates are complex sounds, since they have stop and fricative elements. Implosive consonants, such as the first d in the Russian word poddelat’ (“to counterfeit”), are made without releasing the occlusion. Plosive consonants are the most common.

The active organ may be brought together with an active or a passive organ, leaving an opening for the passage of the expelled air. This type of articulation creates fricative consonants, such as f, v, s, j, x, and l. Some easily movable organ is vibrated to produce the trills. The number of vibrations is usually not great; in Russian, for example, r at the beginning of a word and before a vowel generally consists of two vibrations, and between vowels it consists of only one.

Acoustically, stops are characterized by the rapid appearance of the higher (noise) components of the spectrum. Fricatives are characterized by the absence of an abrupt transition in the consonant spectrum. The spectrum of the trills is characterized by a periodic modulation in intensity.

All consonants are also classified according to the active organ that creates the noise-producing obstruction. Thus, there are labial, lingual, uvular, pharyngeal, and glottal consonants. Labial consonants may be articulated by using both lips (bilabial consonants) or by bringing the lower lip near or into contact with the upper teeth (labiodental consonants). Linguals are classed as front, middle, or back, depending on whether front, middle, or back parts of the tongue are used. The front linguals include apical consonants, for which the active organ is the tip of the tongue (English t and d); dorsal consonants, for which the active organ is the front part of the dorsum of the tongue (Russian t and d); cacuminal consonants, for which the entire edge of the front part of the tongue is raised; and retroflex consonants, for which the tip of the tongue is curled back (English r). According to the passive speech organ, consonants are classed as interdental, dental, alveolar, and postalveolar. Uvular consonants are produced with the uvula or the entire soft palate; the passive organ in this instance is the root of the tongue. Constriction of the pharynx produces pharyngeal consonants. Laryngeal (glottal) consonants result from an occlusion or constriction of the vocal cords.

Acoustically, the more frontal consonants—the labials and front linguals—are characterized by a distribution of energy throughout the entire spectrum and are called diffuse consonants; the consonants produced further back in the mouth are characterized by a relative concentration of energy in the middle portion of the spectrum and are known as compact consonants. Labials and consonants produced far back in the mouth are characterized by a concentration of energy in the lower frequencies of the spectrum and are termed grave consonants. Consonants with a more central articulation are characterized by a concentration of energy in the higher portions of the spectrum and are called acute consonants.

Consonants may be unicentral or bicentral, depending on the number of points at which the speech organs approach or are in contact with each other. This distinction is most commonly made in the case of fricatives and front linguals. Unicentric consonants (sibilants) are formed by bringing only the front part of the tongue near the palate, as in the case of the Russian s and z. Bi-centric consonants (hushing consonants) have a first, front lingual focus and a second focus, either middle lingual, as with the Polish s and z, or back lingual focus, as with the Russian f and 3. Bicen-tric stops with a first labial focus and a second lingual focus occur in the languages of West Africa. Fricatives are also classified according to where the airstream passes: in medial fricatives the air passes over the tongue, as in the case of the Russian s, z, and x, whereas in lateral fricatives the air passes along the sides of the tongue, as in the case of the Russian l. The clicks encountered in the languages of Africa are special types of consonants. They are formed without an airstream, since the back part of the tongue remains in contact with the soft palate during their pronunciation; sound is created by the sucking action of the front or middle part of the tongue or the lips.

The principal types of consonants may be modified, taking on a specific coloration because of what are known as secondary articulations. The most common secondary articulations are palatalization and labialization. Consonants are palatalized by raising the middle part of the tongue to the palate; this appears in the spectrum because of the amplification of some upper frequencies (sharp consonants). Labialization involves rounding and protruding the lips, which results in a lowering and weakening of some upper frequencies (flat consonants). Other, more rarely occurring secondary articulations are velarization, in which the back part of the tongue is raised, as with the Russian hard consonants, especially /; pharyngealization, in which the pharynx is constricted, as in Arabic; and glottalization, in which the vocal cords are brought together and the larynx is raised, as with the globalized consonants in Georgian.

Secondary articulations may serve as distinctive features of phonemes in the same way that primary articulations can. Thus, palatalized (soft) and nonpalatalized (hard) consonants in Russian and labialized (rounded) and nonlabialized (unrounded) consonants in some Dagestan languages are separate phonemes.