13. Vowels

Vowels are voiced sounds in forming which the airstream passes freely without any obstruction through the larynx the mouth cavity make the vocal cords vibrate. Vowels are classified:

in the stability of articulation: (1.l) monothongs - are vowels the articulation of which doesn’t change. The quality of such v-ls is relatively pare [i,e,a:, o:,);, u,3:, ?] ;(1.2) diphthongs in the pronunciation of diphthongs the organs of  speech slide from one v-l position to another within one  syllable. The nuclear of diphthongs is strong distinct the glide is very weak [ei, эi, au, ?u, є?, u?]. (1.3) In the pronunciation of diphthongs the articulation changes just a little bit.

But the difference between the nuclear the end is not so distinct as it is in the case of diphthongs; [i:, u:]. 

The tongue position: horizontal movement of the tongue.  When the tongue is in the front part of the mouth and the  front part of it is raised up to the hard palate a front v-1 is pronounced [i:, e].

When the front of the tongue is raised  towards to the back part of the lard palate the vowel is called central (or mixed) [ ]. When the tongue is in the back part of the mouth and raised up to the soft palate a back  vowel is pronounced [a:, э, э:, u:]. Vertical movement high (or closed) vowels: [i:, u, u:], open (low) vowels [a:, o;]. 

The lip position. When the lips are neutral or spread the vowels are called unrounded.When the lips more or less  round they called rounded [u;u].

Vowel length. All Eng. Monophthongs are   divided into  long[I:, a: u:,?:] and short[I e u a].

14. Diphthongs and diphthongoids

According to Russian scholars vowels are subdivided into: a) monophthongs (the tongue position is stable); b) diphthongs (it changes, that is the tongue moves from one position to another); c) diphthongoids (an intermediate case, when the change in the position is fairly weak).

diphthong, refers to two adjacent vowel sounds occurring within the same syllable. In most dialects of English, the words eye, boy, and cow contain examples of diphthongs.Diphthongs contrast with monophthongs, where only one vowel sound is heard in a syllable. Where two adjacent vowel sounds occur in different syllables, as in, for example, the English word re-elect, the result is described as hiatus, not as a diphthong. Diphthongs often form when separate vowels are run together in rapid speech during a conversation. However, there are also unitary diphthongs, as in the English examples above, which are heard by listeners as single-vowel sounds (phonemes) ı – [eı, aı, ɔı]; u – [au, ǝu]; ǝ – [ıǝ, ɛǝ, ɔǝ, uǝ].

Дифтонгоид - это ударный неоднородный гласный, имеющий в начале или конце призвук другого гласного, артикуляционно-близкого к основному, ударному. [i:, u:]

15. modifications of vowels Modification of vowels. Reduction is a historical process of weakening, shortening or disappearance of vowel sound in unstressed positions. This phenomenon is closely connected with the historical development of the language. R. reflects the process of lexical&gramm. Clanges. The neutral sound represents the reduced form of almost any vowel in the unstressed position. But the quality of an unstressed vowel sound m.b. retained ▪in compound words ▪in borrowings from Latin/French, e.g. [‘gæra:з] R. is connected also with rhythm & sentence stress. R. is realized: ▪in unstr. syll. within words ▪in unstr. form-words, auxiliary and modal verbs, pers, and possessive pronouns. Types of reduction 1. Quantitative (shortening of a long vowel sound) Qualitative (both long and short vowels are shortened till [ə, i, u] Elision (the omission of vowel)