nasal (adj.)
A term used in the PHONETIC classification of speech sounds on the basis of MANNER of ARTICULATION: it refers to sounds produced while the soft PALATE is lowered to allow an audible escape of air through the nose. Both CONSONANTS and VOWELS may be articulated in this way. Nasal consonants (sometimes represented as a class by N or nas) occur when there is a complete CLOSURE in the mouth, and all the air thus escapes through the nose. Examples in English are the final consonants of ram, ran, rang [ram, ran, 
], where the closures are in BILABIAL, ALVEOLAR and VELAR positions respectively. Several other nasal sounds are possible, e.g. in PALATAL positions 
, as in Spanish mañana. VOICELESS nasal sounds also occur, as when a nasal consonant follows [s] in English, e.g. small, snooze. In nasal (or nasalized) vowels, air escapes through nose and mouth simultaneously; the vowels are transcribed with [~] above the symbol, e.g. [ã]. Nasal vowels are opposed to ORAL vowels in a language, as in French and Portuguese. English has no distinct nasal vowels, but nasalization is often heard on English vowels, when they display the articulatory influence of an adjacent nasal consonant, as in mat or hand. The vowel in a word like man may be articulated with the soft palate lowered throughout, because of this influence – an instance of ANTICIPATORY COARTICULATION. Such cases, where the nasality comes from other sounds, would be referred to as ‘nasalized’ vowels; the term ‘nasal vowel’, on the other hand, suggests that the nasality is an essential identifying feature of the sound. A ‘nasalized consonant’, likewise, would refer to a consonant which, though normally oral in a language, was being articulated in a nasal manner because of some adjacent nasal sound.
Stop consonants (and sometimes fricatives) may be articulated with a prenasal onset or post-nasal release, depending on the timing of the velic closure relative to the oral closure: Swahili, for example, has a series of pre-nasalized stops. The opposite term is denasalized, which would be applied only to sounds which normally were articulated with a nasal component (as when one speaks through a blocked nose). In certain clinical conditions, such as cleft palate, abnormal degrees of nasalization may be present: excessively nasal (or hypernasal) speech is here opposed to reduced nasality (or hyponasal speech).
Other nasal effects may be heard in a language. A PLOSIVE sound, for example, when followed by a nasal articulated in the same position, may be released through the nose instead of the mouth, and the resulting auditory effect is one of nasal plosion, as in sudden 
, which is rather more likely than 
. Nasal twang is not a term with a precise phonetic definition, as it refers to any degree of nasal effect in a speaker or ACCENT, seen in contrast with speech which is more oral in character.
The opposition between nasal and oral is given a special technical status in the DISTINCTIVE FEATURE theory of PHONOLOGY, where it works alongside other two-way CONTRASTS as part of the complete specification of a sound system. In Chomsky and Halle’s theory, for example, it is classified as a CAVITY feature, and grouped along with LATERAL under the specific heading of SECONDARY APERTURES.
