In articulatory phonetics, consonants are generally defined as a set of speech sounds that are produced by partial or complete constriction of the vocal tract. Vowels, on the other hand, tend to be produced with a relatively open vocal tract. Consonants also differ from vowels in that consonants are aperiodic (i.e., noisy) and not as sonorant (i.e., do not carry as far). In speech, consonants are often described in terms of their place of articulation, manner of articulation, and voicing.
Consonant sounds are often partly described in terms of where the point of constriction occurs in the vocal tract. Bilabial consonants are made my compressing the lips together (i.e., /m b p/),
Place of articulation is of particular relevance to people who speechread. It is also relevant to cuers since some aspects may be revealed in the non-manual, mouthshapes that accompany cues.
The feature of voicing is
The unique combination of place (where), manner (how), and voicing (whether or not the vocal folds vibrate) makes each consonant acoustically distinctly identifiable.
In Cued Speech, consonant phonemes are represented by handshapes.
Relying on or teaching features of speech.
In the English alphabet, there are 21 consonant letters: Bb, Cc, Dd, Ff, Gg, Hh, Jj, Kk, Ll, Mm, Nn, Pp, Qq, Rr, Ss, Tt, Vv, Ww, Xx, Zz.