Fricative consonant
Fricatives are consonants produced by forcing air through a narrow channel made by placing two articulators close together. These may be the lower lip against the upper teeth, in the case of; the back of the tongue against the soft palate, in the case of German, the final consonant of
Bach; or the side of the tongue against the molars, in the case of Welsh, appearing twice in the name
Llanelli. This turbulent airflow is called
frication. A particular subset of fricatives are the
sibilants. When forming a sibilant, one still is forcing air through a narrow channel, but in addition the tongue is curled lengthwise to direct the air over the edge of the teeth. English, , , and are examples of this. Two other terms are
spirant and
strident, but their usage is less standardized. The former can be used synonymously with "fricative", or to refer to non-sibilant fricatives only. The latter can be used synonymously with "sibilant", but some authors include also labiodental and/or uvular fricatives in the class.