The Nature of Speech Sounds: Revisited
One way to describe speech is to see it as a medium of transmission for language. It is the phonic substance of language, as compared to writing, the graphic substance. That it constitutes the phonic substance presupposes that the spoken medium (as opposed to the written medium) is made up of sounds. To be more specific we relate sounds to speech and refer to them as speech sounds.
This implies that a speaker utters sounds which combine to form syllables (syllables, if they are not of word status) are combined to form words while words are combined to form groups and longer stretches of utterances with which human beings communicate. The whole process of production and perception of speech which we are concerned with in this course is known as speech processing.
3.2 Speech Production: The Focus
Normal people speak very many times each day: to members of their families, to those in their communities and to others in the larger society. Particularly in a situation of first language acquisition, the effortless nature of the acquisition of the speaking skill makes it understandable that some speakers hardly ever ask: What is speech? How is it produced?
For those who study linguistics (particularly those whose interest is mainly in the branch called phonetics), and for those who study the way languages operate, it is important to understand what speech is and how it is produced. These are our concerns here.
3.3 Speech Production Process [involves Initiation, Phonation and Articulation]
3.3.1 Respiratory and Phonatory Stages [vocal folds/chords preferred to vocal lips pls] When air leaves the lungs (where it is normally stored), it moves through the trachea to the larynx which covers and encloses the vocal bands (vocal cords or vocal folds). At the centre of the vocal folds, there is space (the glottis). When this space is closed, the vocal folds are brought together through the action of the elastic membranes which stretch from the front to the back, across the larynx. This closure of the vocal folds naturally leads to a building up of air pressure below them. The air so built up forces itself through the vocal folds in periodic puffs. The vocal folds will then open under this pressure, first from the bottom and then upwards creating a kind of rippling action. The combined effects of the forced opening and closing results in a vibration of the vocal folds. A sound that comes with the vibration is normally voiced. Voice may, therefore, be seen as a technical term that refers to phonation – a pre articulatory output from the vibration of the vocal folds. All voiced sounds in all natural languages are produced when the vocal folds are in a closed position – a position that prepares the way for vibration.
But the vocal folds do not always remain in a closed position: sometimes they are partially open and at other times they may be fully open. When they are partially open, the air that passes through them results in a whisper. When they are fully open, air passes through them without vibration and that results in the ensuing sounds being voiceless. Thus, the vocal folds help us to distinguish between voiced and voiceless sounds and when they assume a posture of intermediate opening, they help us to identify whisper. Perhaps more importantly, the vocal folds help us to distinguish between vowels and consonants: in the realization of vowels, in practically all natural languages, there is a vibration of the vocal folds. This follows the fact that all vowels in all natural languages are normally voiced. On the contrary, consonant sounds in all natural languages are either voiced or voiceless. These statements do not exclude the issue of devoicing which is possible in all cases.
3.3.2 Articulatory Stages
From the vocal folds, the air passes through the pharynx. At this point, the brain carries out a quick, sharp action, directing the soft palate (also called the velum)
particularly the uvula (the pendulous end of the velum), on what to do: the uvula will either be lowered to block the oral cavity or raised to the back wall of the throat to block the nasal cavity.
The blocking of the oral cavity takes place when nasal or nasalized sounds are to be realized. The blocking of the nasal cavity takes place when oral sounds are to be produced. It should however, be noted that in practice that almost any sound can be nasalized to demonstrate organ control although speech defect can also lead to it.
The entire production process can be seen at a glance in Figures 4a/4b below:
Figure 4a: The Speech Production Process in the Upper Vocal Tract
Adapted from courses Washington.edu
Figure 4b: Arrows Showing Airstream from the Lungs to the Trachea
Figs. 4a & 4b. Diagrams showing speech production process.
Self-assessment exercise 2
Attempt a brief discussion of the process of sound production
3.4 Sound Articulation: Specific Issues
We have seen in this course that the terms sound production and sound articulation refer to precisely the same events. So, practically everything we have discussed in this course so far can come under the heading: sound articulation. In this section therefore, we shall tidy up a lot of the things we have so far discussed in this course, but will also place appropriate emphasis on issues which may be more gainfully discussed under the heading sound articulation.
First, we can refer to the organs of speech as the articulators. In that case the articulators may be seen as belonging to two groups – those which are relatively fixed and those which are relatively movable. The fixed articulators are generally said to be passive ones; the movable articulators are generally said to be active ones.
This is accurate from a physical/anatomical viewpoint: a fixed organ is inactive and thus passive from the standpoint of mobility; a movable organ is agile and thus active from the same standpoint of mobility. In phonetic terms however, a passive articulator is not necessarily fixed in the physical or traditional sense: it is simply the articulator that remains motionless, waiting (so to say), for the movable one to get to it for the purpose of a particular sound articulation. The active articulator on the other hand is phonetically the one that ensures or sparks off the articulation of a particular sound. An illustration will make this clear: even though the upper/lower lips are generally classified among the movable organs yet in the realization of sounds the upper lips are (sometimes) the passive articulators while the lower lips are the active articulators, for example in the realization of labio-dental sounds. Also, if in the articulation of a sound, the uvula is made to play rapidly against the back of the tongue, the uvula thus remains as the active articulator while the back of the tongue becomes the passive articulator…It is important to note that articulatory movements are largely upward movements (cf, Abercrombie, 1975:43), i.e. the active articulators which are largely located on the lower side of the vocal tract tend to move upward to meet the passive articulators which tend to be on the upper side of the vocal tract. So it is more accurate to say that while the great majority of the so called fixed organs of speech are passive articulators and the great majority of the so called active articulators are the movable organs, it is the specific role of a given organ at a given instance, that determines passivity or activity.
4.0 CONCLUSION
You have studied in this unit that speech production is a very important event in both phonetics and phonology. From this unit, you are also in a position to appreciate the roles played by specific human organs as well as the stages in the production of speech.
5.0 SUMMARY
From this unit, you have:
(i) revisited the nature of speech sounds; (ii) studied speech production processes;
(iii) identified stages of speech production _ INITIATION WAS LEFT OUT!.
6.0 TUTOR-MARKED ASSESSMENT
6. Briefly state how you would trace the journey of any given sound from the time it leaves the lungs to the time it is produced. Specify the language.
7.0 REFERENCES/FURTHER READING
Abercrombie, D. (1975): Elements of General Phonetics. Edinburgh: Edinburgh University Press.
Clark, J and C. Yallop (1990): An Introduction to Phonetics and Phonology; Oxford; Basil Blackwell.
Eka, D. (1993). Timing in Educated Spoken Nigerian English. Journal of Humanities 3; 1-11
Ward, Ida C. (1972). The Phonetics of English; (5th Edition); Cambridge; Cambridge University Press.
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