6. Articulatory differences between consonants and vowels

Physiological Distinction

In general, consonants can be said to have a greater degree of constriction than vowels. This is obviously the case for oral and nasal stops, fricatives and affricates. The case for approximants is not so clear-cut as the semi-vowels /j/ and /w/ are very often indistinguishable from vowels in terms of their constriction.

Acoustic Distinction

In general, consonants can be said to be less prominent than vowels. This is usually manifested by vowels being more intense than the consonants that surround them. Sometimes, certain consonants can have a greater total intensity than adjacent vowels but vowels are almost always more intense at low frequencies than adjacent consonants.

Phonological Distinction

Syllables usually consist of a vowel surrounded of consonants. A single vowel forms the prominent nucleus of each syllable. There is only one peak of prominence per syllable and this is nearly always a vowel. The consonants form the less prominent valleys between the vowel peaks. This tidy picture is disturbed by the existence of syllabic consonants. Syllabic consonants form the nucleus of a syllable that does not contain a vowel. In English, syllabic consonants occur when an approximant or a nasal stop follows a homorganic (same place of articulation) oral stop (or occasionally a fricative) in words such as "bottle" /bɔtl̩/ or "button" /bʌtn̩/.

The semi-vowels in English play the same phonological role as the other consonants even though they are vowel-like in many ways. The semi-vowels are found in syllable positions where stops, fricatives, etc. are found (eg. "pay", "may", and "say" versus "way").

7. Modifications of vowels in speech

The phonetic process that affects English vowels in connected speech is called reduction. By vowel reduction we mean shortening or weakening of the sound, or, in other words, shortening in length that is usually accompanied by a change in quality. Vowel reduction in unstressed syllables is very common both in English and in Russian. In connected speech vowels can be exposed either to quantitative and qualitative reduction or both. These changes of vowels are determined by a number of factors, such as the position of a vowel in a word and in an utterance, accentual structure, rhythm, tempo of speech.

Quantitative reduction or shortening of vowel length takes place in the following cases:

1. The length of vowel depends on the immediate phonetic environment (positional length). Vowels are the longest in the final position, they are shorter before a voiced consonant and the shortest in a syllable closed by a voiceless consonant, knee - need - neat.

2. Long vowels in form words are shortened in unstressed positions: At last he [i'] has come. Modifications in quality occur in unstressed positions. The most common form of vowel reduction is reduction to schwa [ə]. In its production the tongue is the closest to the neutral position, the lips are unrounded and it is the shortest of all vowels. The pronunciation of schwa instead of some other vowel saves articulatory effort and time. Man [meen] sportsman ['sp;:dsman], conduct ['knndakt] - conduct [kan'dAkt]. You can easily do it [ju' kan i:zrlI ,du Schwa is considered to be the most frequent sound in English. It is obviously the result of the rhythmic pattern in which stressed syllables alternate with unstressed ones. Unstressed syllables are given only a short duration and the vowel in them is reduced.

3. Vowels are slightly nasalized when preceded or followed by a nasal consonant like in man, no, then, mean.