What Is Sibilance?

Sibilance refers to the whistling or hissing sound that accompanies certain English consonants. Take for example the sentence:

  • ‘a snake slithers across the wispy grass
    (the repeated consonant ‘s’ creates a sibilance.)
An agent of sibilance
Sibilance: Snakes make hissing sounds!

The word ‘sibilance’ on its own has a sibilance, and one of the letter ‘s’ sounds is actually created by the letters ‘ce’. It is the resulting sounds that creates a sibilance and not the spelling as we can see in the case of the word “sibilance”.

The trigger of sibilance is the result of high-velocity turbulence in the air flowing out of the speaker's mouth (i.e., forcing the breath through a narrow opening in the teeth). As the air flows through a narrow channel along the tongue, the resulting friction creates a high-pitched “hiss.” The accompanied whistling or hissing effect is a unique feature of the six English consonants known as sibilants:

Sounds such as ‘s’ are higher on a stridency scale, being relatively high-pitched and intense (they display more energy at higher frequencies).

StridencyOpens in new window refers to the perceptual intensity of the sound of a sibilant consonant such as s, sh, ch, z, j, or obstacle fricatives/affricates, which refers to the critical role of the teeth in producing the sound as an obstacle to the airstream. Non-sibilant fricatives and affricates produce their characteristic sound directly with the tongue or lips etc. and the place of contact in the mouth, without secondary involvement of the teeth.

The Importance of Sibilance

Difficulties associated with pronouncing certain English words may be avoided by understanding the concept of sibilance. For example, English learners whose first languages do not have the /θ/ sound will often use the sound /s/ in its place. However, the sound /θ/ is not a sibilant, while the /s/ sound is. Understanding sibilance and what causes it can actually help clarify the difference between these two sounds.

Another example of the usefulness of understancding sibilance is the case of Japanese students, who sometimes add sibilance to a word like “he.” As a result, English listeners will often mistake the “he,” as said by a Japanese speaker, for “she.” Understanding sibilance can also help speakers of Korean who tend to add a vowel sound after final sibilants, and Spanish speakers, who tend to leave off the final /s/ or /z/ from plural nouns.

Further Readings:
Wikipedia Sibilance Opens in new window
Judy B. Gilbert; Clear Speech Teacher's Resource Book: Pronunciation & Listening;Sibilants Opens in new window
Hand Book for Acoustic Ecology: Sibilance Opens in new window