The lips may be more or less puckered or in the pronunciation of all the vowels and most of the consonants. This gives a peculiar resonance effect. English o in note and u in tune are rounded. German ii and French u are rounded long e (as in meet or mere).
Accent is of two kinds. Stress accent is a variation in the energy of utterance (ampli tude of vibration) of successive (a) words, (b) syllables, (c) sounds or (d) parts of the same sound; (a) constitutes sentence accent, (b) is word accent, (c) and (d) syllable accent. Pitch accent is a variation of musical tone (rate of vibration) similarly affecting sounds, syllables and words. In most, if not all, languages both types occur. In English stress predominates.
Comparatively few speech movements and sounds are here described. Those actually produced are innumerable; they run into the millions or even billions. Each nation has a group of some three score "mains sounds and countless minor variations. Each individual has his own way of speaking; we easily recog nize his voice; but even he varies his pronuncia tion from day to day, nay, even from minute to minute. Here, as everywhere else in animal and even vegetable life, nothing is fixed. As the old Greek philosopher said, pasta rhei, 'everything is in a flux?) Movement and change are life; rigidity is death.
Sound As already stated, Ph o netics is applied psychology of movement. The muscles used in speech, though highly trained, act as other muscles act. You cannot close the eyes and draw with a sharp pointed pencil 10 lines exactly one inch long. A ball player cannot throw the ball twice through exactly the same point over the plate. If he does it is an accident. The best marksman rarely hits the exact centre of the bull's eye. So in speech no one can repeat at will exactly the same move ment, much less a group of movements neces sary to the production of a given sound. There will always be variations in range, direction, duration and co-ordination. The variations are slight, as are those of an expert marksman, and the consequent variations in sound are either unnoticeable to the "naked) ear or, if noticeable, are really unnoticed, since our at tention is wholly absorbed in what a person is saying and we give only the slightest heed to the details of sound. It is only occasionally
that variations occur large enough to thrust themselves on our attention. Then we call them mispronunciations.
But the variations, though small and un noticed, will in a given community under favorable conditions accumulate in a given di rection. Thus there will be a slow but steady shift in a given direction, which in time will result in entirely different movements, that is, in entirely dffferent sounds. For example, the word stone in Early English was written stone and pronounced with the sound of a as in father; in Chaucer's time the same vowel had the sound of au in bought and the spelling was reformed to stone. Since then it has shifted to the present pronunciation. The following types of changes occur: (1) Cessa tion of movement. Sounds become silent, as most e's, at the end of English words, gh in high, b in lamb, etc. This change may be facilitated by a stress accent on the preceding syllable. (2) Increase or decrease in the duration of the movement. Example: The Indo-European extra long diphthongs äti, etc., became the ordinary length diphthongs di, ei, oi, etc., in Latin. (3) Variation in ex tent of movement. This variation affects, for example, the shape of the mouth cavity and the tension of the vocal cords, giving rise to varia tion in vowel quality, as in stone, cited above, and characterizing such shifts as that of Indo-European palatal k to fricatives in San sent and Slavic. (4) Anticipation or delay of individual movements composing a group. Such are the voicing of previously voiceless consonants and vice-versa; assimilation both progressive and regressive; and u Umlaut. (5) Change in the order of movements. This is a fertile source of mispronunciation, but ap pears to have caused few historical changes.
The causes of these changes are partly physiological and partly psychological, being due to changing chemical conditions in the muscle or to changes in state of mind. Wide spread regularity observed in these changes has given rise to the belief that, like other natural phenomena, they follow regular laws; but the conditions determining the changes are extremely complex and difficult to control. Such laws are Grimm's law of consonant change, with its modifications by Verner and Burgmann.