FRICATIVE
A fricative is the type of consonant that is formed by forcing air through a narrow gap in the oral cavity so that a hissing sound is created. Typically air is forced between the tongue and the place of articulation for the particular sound. Try it yourself. Say the /f/ in fin /fɪn/, the /θ/ in thin /θɪn/ and the /ʃ/ in shin /ʃɪn/. You should be able to feel the turbulence created by the sounds. It is possible to maintain a fricative sound for as long as your breath holds out. This is very different from a plosive sound. Other fricatives include the /v/ in van, the /s/ in sin, the /h/ in hat /hæt/, the /ð/ in that /ðæt/, the /z/ in zoo /zu:/ and the /Ʒ/ sound in genre /ˈʒɑ:nrə/.
Fricative consonants result from a narrowing of the speech canal that does not achieve the full closure characteristic of the occlusives. The shape and position of the lips and/or tongue determine the type of fricative produced. Phoneticians usually distinguish between so-called true fricatives and the related class of spirants. During the production of a fricative, the airstream can be directed in several ways. First, in the case of true fricatives, the tongue channels the air through the center of the mouth (like in the case of the dorsal fricatives). Second, the tongue can also channel the air down the side(s) of the mouth (like in the case of the lateral fricatives). Finally, in the case of labial and dental fricatives, the shape and position of the tongue is not important. This makes sense because the place of articulation is not, strictly speaking, in the oral cavity at all.
[f] is a voiceless labiodental fricative. The lower lip is brought close to the upper teeth, occasionally even grazing the teeth with its outer surface, or with its inner surface, imparting in this case a slight hushing sound. Considering its place of articulation, it is unimportant to class this sound as dorsal or lateral fricative. [v] is a voiced labiodental fricative. Its articulation is the same as [f], but with vibration of the vocal cords. Like [f], considering its place of articulation, it is unimportant to class [v] as dorsal or lateral fricative.
Among the fricatives are ones described as hissers and hushers. The realization of a hisser requires a high degree of tension in the tongue: a groove is formed along the whole length of the tongue, in particular at the place of articulation where the air passes through a little round opening. English hissers are /s/, /z/, /ʧ/, and /ʤ/. The hushers are produced similarly, but with a shallower groove in the tongue, and a little opening more oval than round. The lips are often rounded or projected outwards during the realization of a husher. English hushers are /ʃ/, and /ʒ/.
Spirants involve the same restriction of the speech canal as fricatives, but the speech organs are substantially less tense during the articulation of a spirant. Rather than friction, a resonant sound is produced at the place of articulation.
[s] is a voiceless alveolar fricative (also a hisser). This apico-alveolar hisser is produced by bringing the end of the tongue close to the alveolar ridge. Hissers like /s/ can be divided into three categories, according to the precise part of the tongue that comes into play: (a) coronal hissers which involve the front margin of the tongue (as in English), (b) apical hissers which involve the very tip or apex of the tongue (as in Castilian Spanish), and (c) post-dental hissers where the front part of the tongue body is involved (as in French). The quality of the sound is noticeably altered in these three types of hissers. The IPA uses diacritical marks to indicate distinctions of this magnitude. [z] is a voiced alveolar fricative (and a hisser). The same mechanism that produces [s] also produces [z] but with vibration of the vocal cords. In general, the remarks made for the voiceless sound are equally valid for the voiced variant. Other hissers are [ʧ] and [ʤ]. [ʧ] is a voiceless palatal fricative. The tongue body forms a groove and approaches the hard palate. In terms of general tongue shape, this articulation qualifies as a hisser. [ʤ] is a voiced palatal fricative. It is articulated in the same way as [ʧ] but with vibration of the vocal cords. [ʃ] is a voiceless alveolar fricative (and a husher). The tip of the tongue touches the alveolar ridge. The groove in the center of the tongue is shallower than is the case for hissers. [ʒ] is its voiced counterpart.
Basically, friction and fricatives develop from tense articulations. When the articulation is lax, resonance, and thus a spirant, occurs. Also realize that many spirants can be thought of as the lax counterparts of stop consonants. English interdentals /ð/ and /θ/ are spirants.
[θ] is a voiceless dental spirant. The tongue tip is held close to the upper teeth, either behind them (dental) or just underneath them (the interdental articulation). This spirant is the lax counterpart of the stop [t]. Considering its place of articulation, it is unimportant to class this sound as a dorsal or lateral fricative. [ð] is the voiced counterpart of /θ/. Its articulation is the same as /θ/ but with vibration of the vocal cords. This spirant is the lax counterpart of the stop [d].
Laterals are generally considered to be a special case, since physically speaking they could be grouped among the fricatives and spirants. They are called laterals since, during their production, the back of the tongue makes contact with the hard palate while the front of the tongue sinks down, channeling the air laterally around the tongue, down the side (or sometimes both sides) of the mouth. On the other hand, for non-lateral articulations, the back of the tongue rests against the top molars, and the air flows over the tongue down the center of the mouth. There are two distinct types of lateral: (a) lateral fricatives, where the articulation, requiring a great deal of muscular tension, resembles that of the fricatives (except for the position of the tongue), and (b) non-fricative lateral, often called liquids, whose articulation is very close to the spirants. It is interesting to note that the location of the lateral channel through which the air flows is unimportant. That is, whether it is on the left, the right, or both sides of the mouth, the nature of the sound produced is unchanged. English laterals are usually non-fricative. In addition, no distinction is made between voiceless and voiced variants because it is very rare for a language to distinguish laterals according to voice. English liquids are /r/ and /l/.
