Nasal-stop:

A nasal consonant is one in which the air escapes only through the nose. For this to happen, two articulatory actions are necessary: firstly, the soft palate (or velum) must be lowered to allow air to escape past it, and secondly, a closure must be made in the oral cavity to prevent air from escaping through it.

/m/

The lips form a closure as for /p, b/, the soft palate is lowered, adding the resonance of the nasal cavity to those of the pharynx and the mouth chmber closed by the lips.

/n/

The tongue forms a closure as for /t, d/; the soft palate is lowerd, adding the resonance anasal cavity of the pharyncs and of that part of the mouth cahmber behind the alveolar closure; the lip position will depend on that adjacent vowels

/ ŋ /

A closure is formed in the mouth between the back of the tongue and the velum as for /k, g/; the soft palate is lowered, adding the resonance of the natural cavity to that of the pharynx and that small part of the mouth chamber ehing the velar closure, the lip position will depend upon that of the preceding vowel

Semi-vowels (glide):

It has long been recognised that most languages contain a class of sound that functions in a way similar to consonants but is phonetically similar to vowels: in English, for example, the sounds / w / and / j / (as found in 'wet' and 'yet') are of this type: they are used in the first part of syllables, preceding vowels, but if / w / and / j / are pronounced slowly, it can be clearly heard that in quality they resemble the vowels [u ] and [ i ] respectively. However, a glide is a sound which doesn’t have a steady place of articulation, that is to say, the actual point which the essential vocalic glide begins depends on the nature fo the following sound. The term semi-vowel has been in use for a long time for such sounds, though it is not a very helpful or meaningful name; the term approximant is more often used today.

Despite the fact that semi-vowels or glide are, in phonetic terms, generally vocalic, they are trated within the consonant class, mainly because their function is consonantal rather than vowel-like. Their consonant function is emphasized by the fact that the articles have their preconsonantal form, / ðə / instead of / ði / and the indefinite article "a" rather than "an", when are followed by /j/ and /w/:


Pre-consonantal form:

A year
/ə ˈjɪə || ə ˈjɪər/ --->correct
/ən ˈjɪə || ən ˈjɪər/--->incorrect


The yard
/ ðə jɑːd/ || / ðə jɑːrd/--->correct
/ ði jɑːd/ || / ði jɑːrd/--->incorrect


A wound
/ə ˈwuːnd/--->correct
/ ən ˈwuːnd/--->incorrect

/j/

It is articulated by the tongue assuming the position for the front half-close to close vowel (depending on the degree of opennes of the following sound) and moving away immediately to the position of the following sound.

/w/

It is articulated by the tongue assuming the position for a back half close vowel (depending upon the degree of openness of the following sound) and moving away immediately to the position of the following sound

Affricate:

it refers to a sound made when the air-pressure behind a complete closure in the vocal tract is gradually released; the initial release produces a plosive, but the separation which follows is sufficiently slow to produce audible friction, and there is thus a fricative element in the sound also. However, the duration of the friction is usually not as long as would be the case of an independent fricative sound.

Liquid:

A term used by some phoneticians in the classification of speech sounds, referring collectively to all the apico-alveolar sounds of the types [l] and [r]. Liquid sounds have an identifiable constriction of the airflow but not one that is sufficiently obstructive to produce fricative noise, compression or the diversion of airflow through another part of the vocal tract as in nasals. This category includes:

1.- Lateral liquid: it refers to any sound where the air escapes around one or both sides of a closure made in the mouth, as in the various types of /l/ sounds.

/l/

The soft palate being in its raised position shutting off the nasal resonator, the tip of the tongue is in contact with the upper teeth ridge, allowing the air to escape on both sides or, in the case of a unilateral tongue-rim closure on the upper side teeth, on one side.



2.- Approximant liquid: This is a phonetic term of comparatively recent origin. It is used to denote a consonant which makes very little obstruction to the airflow. In English the consonant that has this manner of articulation is / ɾ/ and this phoneme is used such in American accent as British accent. The former replace the /d/ and /t/ intervocalically, e.g. botter and body. The latter replace it just the /d/, for instance anybody, added. However, in British accent usually is used in informal contexts


American accent ----- v/s----- British accent

Butter / bʌɾ.ər/-------------- / bʌt.ə/
Body / bɑː.ɾi/ --------------- /ˈbɒ. ɾi/ (informal)

/ ɾ/

The tip of the tongue produces
a flapped articulation or a rapid contact against the alveolar ridge and returned to the postiong of rest




3.-Retroflex liquid: it refers to a sound made when the tip of the tongue is curled back in the direction of the front part of the hard palate – in other words, just behind the alveolar ridge.

/r/

The soft palate being raised and the nasal resonator shut off, the tip of the tongue is held in a position near to, but not touching, the rear part if the uppper teeth ridge; the centrarl part of the tongue is lawered, with a general contraction of the tongue, so that the effect of the tongue position is one of hollowing and slight retroflexion of the lip. The air-stream is thus allowed to escape freely, without friction, over the centre part of the tongue. The lip position is determined by that of the following vowel.

Fricative:

Two organs are brought and held sufficiently close together for the escaping air-stream to produce strong friction. This friction may or may not be accompanied by voice. The quality and intensity of fricative sounds varies greatly, but all are acoustically composed of energy at relatively high frequency.

/f, v/

The soft palate being raised and the nasal resonator shut off, the inner surface of the lower lip makes a light contact with the edge of the upper teeth, so that the escaping air produces friction.

/ θ, ð/

The soft palate being raised and the nasal resonator shut off, the tip of the tonge make a light contact with the edge and inner surface of the upper incisors and a firmer contact with the upper side teeth, so that the air escaping between the forward surface of the tongue and the indisors caused friction.

/s, z/

The tip and the blade of the tongue make a light contact with the upper alveolar ridge, and the side rims of the tongue a close contact with the upper teeth. The air-stream escapes by means of a narrow groove in the centre of the tongue and causes friction between the tongue and the alveolar ridge

/ ʃ, ʒ/

The tip and blade of the tongue make a light contact with the alveolar ridge, the front of the tongue being raised at the same time in the direction of the hard palate and the side rims of the tongue being in contact with the upper teeth.

/h/

The air is expelled from the lungs with considerable pressure, causing some friction throughout the vocal tract, the upper part of wich is shaped in readiness for the articulation of the following vowel

Plosive or stop

They are produced by forming a complete obstruction to the flow of air out of the mouth and nose, and normally this results in a build-up of compressed air inside the chamber formed by the closure. When the closure is released, there is a small explosion that causes a sharp noise. Plosives are among the first sounds that are used by children when they start to speak (though nasals are likely to be the very first consonants).

/p, b/

The soft palate being raised and the nasal resontor shut off, the primary obstacle to the air-stream is provided by the clausure of the lips.

/t, d/

The blade of the tongue forms a constriction of complete closure with the alveolar ridge.

/k, g/

The soft palate being raised and the nasal resonator shut off, the primary obstacle to the air stream is formed by a clousure made between the back of the tongue and the soft palate. Lung air is compressed behind this closure