English Vowels and Consonants: Classification


The organs of speech are capable of uttering many different kinds of sounds. From the practical point of view, it is convenient to distinguish two types of speech sounds: vowels and consonants.

A vowel is a voiced sound produced in the mouth with no obstruction to the air stream. The air stream is weak. The tongue and the vocal cords are tense.

A consonant is a sound produced with an obstruction to the air stream. The organs of speech are tense at the place of obstruction. In the articulation of voiceless consonants, the air stream is strong, while in voiced consonants it is weaker.

If we want to investigate the functions of vowels and consonants in speech, we first need to think about at which ‘positions’ they can occur in the speech chain and how the two classes of sounds can be combined with one another.

If you think about the patterns in all the languages you know and what kind of patterns they exhibit, you will probably soon realize that no language is composed simply of either vowels or consonants, but that there has to be some kind of alternation between them.

In this alternation, vowels tend to play the central role, and consonants or semi-vowels/approximants fulfill something of a ‘bridging’ function to ‘smooth’ the transitions between the vowels. Most systems for characterizing syllables, therefore, assume that the vowel – or at least something that has some kind of vocalic ‘function’ – has to form the center of any syllable.

This ‘vocalic’ element is usually referred to as the core or rhyme and a consonant or group of consonants (cluster) preceding the rhyme is called the onset. The rhyme itself can either consist of a single peak 1 or a peak followed by a closing consonantal element called a coda. In diagrams, such as the following, the syllable is often indicated by a lowercase Greek letter sigma ( σ ).

Consonants are the bones of a word and give it its basic shape. English accents differ mainly in vowels; the consonants are more or less the same wherever English is spoken. So, if your vowels are not perfect you may still be understood by the listener, but if the consonants are imperfect there may be some misunderstanding.

On the articulatory level the consonants change:

  1. In the degree of noise ( noise consonants – sonorants );
  2. In the manner of articulation (it is determined by the obstruction: complete – the organs of speech are in contact and the air stream meets a closure in the mouth or nasal cavities; incomplete – the active organ of speech moves towards the point of articulation and the air stream goes through the narrowing between them; and momentary );
  3. In the place of articulation (it is determined by the active organ of speech against the point of articulation).

Vowels are sounds of pure musical tone while consonants may be either sounds in which noise prevails overtone ( noise consonants ) or sounds in which tone prevails over noise ( sonorants ).

An obstruction is formed in the articulation of sonorants as well, but the air passage is wider than in the formation of noise consonants. The air stream is weak and it produces very little friction. That is why the articulation of sonorants' tone prevails over the noise.

The English vowel phonemes are divided first of all into two large groups: monophthongs and diphthongs . This division is based on the stability of articulation .

A monophthong is a pure (unchanging) vowel sound. In its pronunciation the organs of speech do not perceptibly change their position throughout the duration of the vowel – [i], [i:], [e], [æ], [ɒ], [ʊ], [ʊ:], [ʌ], [ə], [ɑ:], [ɔ:] and [ɜ:].

A diphthong is a complex sound consisting of two vowel elements pronounced so as to form a single syllable. In the pronunciation of a diphthong, the organs of speech start in the position of one vowel and glide gradually in the direction of another vowel, whose full formation is generally not accomplished. The first element of an English diphthong is called the nucleus . It is strong, clear and distinct. The second element is rather weak. It is called the glide.

There are eight diphthongs in English:

  • three with a glide towards [i] – [ei], [ai], and [ɔi]
  • two with a glide towards [ʊ] – [aʊ] and [əʊ]
  • three with a glide towards [ə] – [iə], [ɛə] and [ʊə].

Besides these diphthongs, there are two vowels in English ([i:] and [ʊ:]) which may have a diphthongal pronunciation: in the articulation of these vowels the organs of speech change their position but very slightly. These vowels are called diphthongized vowels , or diphthongoids .

In vowel production, the tongue may move horizontally (forward and backward) and vertically (up and down).

The English monophthongs may be classified according to the following principles:

  1. According to the tongue position.
  2. According to the lip position.
  3. According to the length of the vowel.
  4. According to the degree of tenseness.

1. Stability of articulation

Monophthongs ( 12)

Diphthongs ( 8)

2. Length of articulation

Long – i:, u:, ɑ :, ɔ :, ɜ :

Short – i, e, æ, ɒ , ʌ , ʊ , ə

3. Degree of muscular tension

Tense – i:, u:, ɑ :, ɔ :, ɜ :

Lax – i, e, æ, ɒ , ʌ , ʊ , ə

4. Lip participation


(labialized) u:, ʊ , ɔ :, ɒ

Unrounded (nonlabialized)

i, e, æ, ʌ ,ə, i:, ɑ :, ɜ :

5. Vertical movement of the tongue

6. Horizontal movement of the tongue

fully front

front retracted



back advanced

fully back



narrow variety



broad variety





narrow variety



broad variety




narrow variety




ɒ ɑ: