Spirant

In phonetics, a spirant is a consonant sound produced by forcing air through a narrow channel in the vocal tract, causing audible friction. This friction distinguishes spirants from other consonant types like stops (which block airflow momentarily) and nasals (which direct air through the nasal cavity). Spirants are often voiced (vibrating vocal cords) or unvoiced (no vocal cord vibration), each pair sharing a similar place of articulation like labiodental (f, v) or dental (θ, ð). The intensity of the friction determines the sonority of the spirant. The term 'spirant' is sometimes used interchangeably with 'fricative', although some linguists reserve 'fricative' for sounds with stronger friction.

Spirant meaning with examples

• The pronunciation of the 'f' in 'fly' showcases a classic labiodental spirant. Air is forced between the lower lip and upper teeth, creating a distinct friction sound. The absence of a complete airflow blockage highlights this consonant's spirant nature, distinguishing it from sounds like 'p'. This airflow generates the spirant's characteristic hissing component.
• The 'th' sound in 'thin' (θ) represents an example of a voiceless dental spirant. The tongue lightly touches the back of the upper teeth. This constricted airflow then yields an auditory friction effect, forming the spirant. This is compared to the 'd' in 'din' (voiced), it demonstrates how a spirant can be unvoiced while maintaining its consonant-based phoneme form.
• The 's' sound in 'sun' demonstrates a voiceless alveolar spirant; the tip of the tongue sits behind the alveolar ridge. The compressed air travels through a small space, and the spirant's effect on phoneme formation takes place. Contrast this with the 'z' in 'zoo' (voiced) which also demonstrates a spirant effect through friction.
• The German 'ch' sound, as in 'Bach', exhibits a velar spirant produced by the back of the tongue against the soft palate. This friction creates a unique auditory quality. It can be more subtle than alveolar spirants. This consonant, a spirant by nature, does not block airflow entirely.