Sibilant consonant

A sibilant, or a strident fricative, is a type of fricative, made by speeding up air through a narrow channel and directing it over the sharp edge of the teeth.

Sibilants are louder than their non-sibilant counterparts, and most of their acoustic energy occurs at higher frequences than non-sibilant fricatives. [s] has the most acoustic strength at around 8,000 Hz, but can reach as high as 10,000 Hz. [ ʃ ] has the bulk of its acoustic energy at around 4,000 Hz, but can extend up to around 8,000 Hz.

Of the sibilants, the following have IPA symbols of their own:

• s, z alveolar
• ʃ, ʒ domed post-alveolar
• ɕ, ʑ palatalized post-alveolar
• ʂ, ʐ palatal (sub-apical retroflex)

Some authors, as for instance Chomsky & Halle (1964), group [ f ] and [ v ] as sibilants, whereas more recent works as for instance by Ladefoged & Maddieson (1996), group them together with the bilabial fricatives [ ɸ, β ] as non-sibilant anterior fricatives.

The sibilant/non-sibilant distinction is especially important in English. Most people consciously know that to pluralize a regular English noun, they simply add an -s to it. But what they know only subconciously is that English plurals can take three forms (allomorphs), those being [s], [z], and [əz]. [s] occurs after most voiceless sounds, and [z] occurs after most voiced sounds. The sequence [əz] fills in the rest, and occurs after sibilants, i.e. [s, z, ʃ, ʒ]. Thus, distinguishing between sibilants and non-sibilants is extremely important in English.

See also

• strident vowel