In
articulatory phonetics, a
consonant is a
speech sound that is articulated with complete or partial closure of the upper
vocal tract, the upper vocal tract being defined as that part of the vocal tract that lies above the
larynx. Consonants contrast with
vowels.
Since the number of consonants in the world's languages is much greater than the number of consonant letters in any one alphabet, linguists have devised systems such as the International Phonetic Alphabet (IPA) to assign a unique symbol to each attested consonant. In fact, the Latin alphabet, which is used to write English, has fewer consonant letters than English has consonant sounds, so digraphs like "ch", "sh", "th", and "zh" are used to extend the alphabet, and some letters and digraphs represent more than one consonant. For example, many speakers are not aware that the sound spelled "th" in "this" is a different consonant than the "th" sound in "thing". (In the IPA they are transcribed ð and ?, respectively.)
The word consonant comes from Latin oblique stem consonant-, from consonans (littera) "sounding-together (letter)", a loan translation of Greek s?µf???? sýmphonon.[1] As originally conceived by Plato,[2] sýmphona were specifically the stop consonants, described as "not being pronounceable without an adjacent vowel sound".[3] Thus the term did not cover continuant consonants, which occur without vowels in a minority of languages, for example at the ends of the English words bottle and button. (The final vowel letters e and o in these words are only a product of orthography; Plato was concerned with pronunciation.)
However, even Plato's original conception of consonant is inadequate for the universal description of human language, since in some languages, such as the Salishan languages, stop consonants may also occur without vowels (see Nuxálk), and the modern conception of consonant does not require cooccurrence with vowels.
