Peter Roach)
4 voicing and consonants
4.1 The larynx
We begin this chapter by studying the larynx. The larynx has several very important functions in speech.
Its main structure is made of cartilage.
Inside the “box” made by these two cartilages are the vocal folds, which are two thick flaps of muscle rather like a pair of lips; an older is vocal cords.
We use the word glottis to refer to the opening between the vocal folds. If the vocal folds are apart we say that the glottis is open.
If they are pressed together we say that the glottis is closed.
i) Wide apart: The vocal folds are wide apart for normal breathing and usually during voiceless consonants like p, f, s
ii) Narrow glottis: If air is passed through the glottis when it is narrowed, the result is a fricative sound for which the symbol is h: a voiceless glottal fricative.
iii) Position for vocal fold vibration: When the edges of the vocal folds are touching each other, air passing through the glottis will usually cause vibration be varied. Three main differences are found:
i) Variations in intensity, ii) Variations in frequency, iii) Variations in quality
4.3 Plosives
A plosive is a consonant articulation with the following characteristics:
One articulator is moved against another to form a stricture .After this stricture has been formed and air has been compressed behind it; it is released. The escape of air will produce noise loud enough to be heard. This noise is called plosion. There may be voicing during part or all of the plosive articulation.
i) The first phase is when the articulator or articulators move to form the stricture for the plosive. We call this the closing phase.
ii) The second phase is when the compressed air is stopped from escaping. We call this the compression phase.
iii) The third phase is when the articulators used. To form the stricture are moved so as to allow air to escape. This is the release phase.
iv) The fourth phase is what happens immediately after (iii).
4.4 English plosives
English has six plosive consonants: p, t, k, b, d, g.
All six plosives can occur at the beginning of a word (initial position), between other sounds (medial position) and at the end of a word (final position).
4.5 Fortis and lenis
The voiceless plosives p, t, k are sometimes called fortis (meaning ‘strong’) and b, d, g are then called lenis (meaning ‘weak’).