3.1 Vowels

From a phonological point of view, vowels are units of the sound system which typically occupy the middle of a syllable, as in “cat” or “big”. Vowels involve the vibration of the vocal cords, and shaping of the mouth.

The various qualities (timbres) of English vowels are determined by the oral resonator - its size, volume and shape. The resonator is modified by the most movable speech organs — the tongue and the lips. Moreover, the quality of a vowel depends on whether the speech organs are tense or lax and whether the force of articulation weakens or is stable.

The main principles according to which vowels are classified:

• according to the horizontal movement of the tongue:

• according to the vertical movement of the tongue;

• according to the position of the lips;

• according to the degree of the muscular tension of the articulatory

organs;

• according to the force of articulation at the end of a vowel;

• according to the stability of articulation;

• according to the length of a vowel.

1 According to the horizontal movement of the tongue, English vowels are classified into front, central and back.

2 According to the vertical movement of the tongue, English vowels have been traditionally subdivided into close (high), mid and open (low).

3 According to the position of the lips, i.e. whether they are rounded, spread or neutral, English vowels are classed into rounded and unrounded.

4 According to the degree of muscular tension, English vowels are classified into tense and lax. Thus, for instance, English /i:/ and /u:/ are characterized as tense, because the speech organs that participate in their formation (the tongue and the lips) are considerably tensed. In the articulation of short /ʊ/ and /ɪ/ these organs are relatively relaxed, so these vowels are characterized as lax.

5 According to the force of articulation at the end of the vowel (the character of the end), English vowels are subdivided into free and checked.

Free vowels are pronounced in an open syllable with a weakening in the force of articulation towards their end, i.e. they have a fading character. These are all the English long monophthongs and diphthongs and unstressed short vowels. Checked vowels are those in the articulation of which there is no weakening of the force of articulation. They are pronounced abruptly at the end, immediately followed by a consonant that checks them. These are historically short vowels under stress.

6 According to the stability of articulation, English vowels are classed into monophthongs / ɑ:, ɔ:, ɜ:, e, æ, ʌ, ɒ, ʊ, ɪ, ə/, diphthongs /eɪ, aɪ, ɔɪ, аʊ, ǝʊ, ɪə, eǝ, ʊə/ and diphthongoids /i: , u:/.

Monophthongs are made by a movement of the tongue toward one position in the mouth. Diphthongs are vowels which consist of a movement, or glide, from one position to another.

7 According to their length, English vowels are divided into long /і:, ɑ:, ɔ:, u:, ɜ:/ and short /e, æ, ʌ, ɒ, ʊ, ɪ, ə/.

Table 1 – English Vowels

Height Place	Front	Central	Back
High (close)	i: ɪ ɪə		ʊ ʊə u:
Mid	e eɪ eǝ	ɜ: ǝ ʌ ǝʊ
Low (open)	æ аʊ aɪ		ɒ ɔ: ɔɪ ɑ: