A consonant is one of the sounds of language that is not a vowel - that is, it is a sound produced with some audible friction or some perceptible stoppage of the flow of air through the organs of speech. The easiest way to know the consonant sounds of English is to look at the letters that are used to represent them. These are normally reckoned to be 20 in number - although this is only a rough approximation, as the number includes two semi-vowels; and several of the consonant letters can be used for more than one sound. (There is also the confusing fact that several consonant sounds are represented in English by a two-letter combination, like -th- and -sh- - and this apart from silent letters.)
Consonants are listed in the order of the 'place of articulation' (= part of the mouth in which they are produced). Most places of articulation produce a pair of consonants: one member of each pair is voiced and the other unvoiced.
- bilabials are produced with both lips. p is unvoiced; b voiced
- labio-dentals involve the lower lip and the teeth: f unvoiced, v voiced
- dentals are made the tip of the tongue on the teeth: th (as in 'think') unvoiced, and th (as in 'then') voiced
- alveolars are made with the tongue on the ridge behind the upper teeth (the 'alveola'): t unvoiced and d voiced. These are stops
- The fricatives s (unvoiced) and z (voiced) are also alveolar
- palatals are made with the blade of the tongue on the hard palate (the centre of the roof of the mouth). -sh- is unvoiced; -zh- voiced
- velars are made at the soft palate, towards the rear of the roof of the mouth: k unvoiced, and g voiced.
- There are also three nasals in English, all involving air passing through the nose: m (bilabial), n (alveolar), and -ng (velar)
- The liquids l and r are produced in the post-alveolar region
- there are two glottals (sounds made in the throat) to be heard in English: h and the informal glottal stop, which is not recognised in written English