Consonant

A consonant is a speech sound in which the air is at least partly blocked or any letter which represents this.Concise Oxford English Dictionary. Consonants may come singly (by themselves) or in clusters (two or more together), but must be connected to a vowel to form a syllable. All the letters of the English alphabet are both consonants and vowels.

Notice that the consonant (C) and vowel (V) notation does not match the letters of English spelling in a one-to-one relationship (e.g. 'th' is one sound), but rather individual sounds.

Words with single consonants include:
 Go (CV), which has one consonant and one vowel in that order
 On (VC), which has one vowel and one consonant in that order
 Ton (CVC), which has a consonant, a vowel, and another consonant in that order

Words with consonant clusters include:
 Pro (CCV), which has two consonants in-a-row and one vowel afterwards
 Old (VCC), which has one vowel and two consonants in-a-row afterwards 
 Spree (CCCV), which has three consonants in-a-row and one vowel afterwards, and finally one consonant
 Arcs (VCCC), which has one vowel and three consonants in-a-row afterwards
 Strengths (CCCVCCCC), which has three consonants in-a-row, one vowel afterwards, and finally four consonants in a row

Consonants have friction when they are spoken, mostly using the position of the tongue against the lips, teeth and roof of the mouth. b and p are plosives, using the lips to produce a tiny sharp sound. Phonetics texts give more details, with diagrams. Consonants may be voicedSound pronounced with the vibration of the vocal cords or unvoiced.Sound pronounced without the vibration of the vocal cords The th in the is voiced, but in breath is not.

There are 21 consonant letters in English, for 24 consonant sounds in most English accents.Crystal, David 1995. The Cambridge encyclopedia of the English language. Cambridge.p242 Because of the history of the English language, there is no neat one-to-one relationship between letter and sound. th and ch each stand for a single sound, and x in fox stands for two sounds (ks). All these letters are consonants:
B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, W, X, Y and Z (and sometimes A, E, I, O and U). W and Y are often used as consonants, but they are sometimes used as vowels. For example, in the word yellow, Y is a consonant, but in the word happy, it is a vowel.

The rest of the letters of the alphabet are called vowels. Vowels are undertone, for there are about 20 vowel sounds in most English accents.p237 The vowels are:
A, E, I, O and U (and sometimes W and Y)

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