The most essential speech unit, complete and independent enough to function as a unit of communication, is the sentence. It can perform this function not only because it consists of words that ate made up of definite sounds, have a definite meaning, and follow each other in a definite order according to the rules of the language, but also because it possesses definite phonetic features, without which the sentence cannot exist. These features are closely connected with the meaning of the utterance as a whole and carry important information that the word of the utterance do not convey. They are superimposed upon the sound making up the sentence in the process of speech and are inseparable from it.
These features are called prosodic, or supra – segmental and include speech melody, sentence – stress, tempo rhythm, pauses. So intonation is a complex of these prosodic features. Of all these prosodic and phenomena the most important are speech melody and sentence – stress.
The main functions of intonation are:
(a) sentence – forming
(b) sentence – delimiting
(c) distinctive
(d) attitudinal
(a) Intonation, along with words and grammatical structure, is an indispensable feature of the sentence. A chain of words correctly used according to grammatical rules does not necessarily make an unambiguous utterance with a clear communicative aim, if pronounced without differentiations in pitch and stress. For instance, "He's passed his exam" may be taken for a statement, or a question, or an exclamation, while with a definite intonation contour superimposed on this chain of words, the communicative aim of the utterance is clearly revealed.
Compare:
He's passed his e xam. – A statement of fact.
He's passed his e xam? – A question.
He's passed his e xam ? – A question + surprise.
He's passed his e xam! – An exclamation.
He's passed his e xam. – A statement + implication.
(The implication may be: So he must know something.
He's probably not so lazy after all. Now he may take a rest, etc.)
(b) The end of a sentence is always recognized by a pause of varying length combined with a moving (or nuclear) tone on the most important word of the sentence; the end of a non – final sense – group* is usually signalled by a shorter pause in combination with a nuclear tone on the semantic centre of the sense – group.*
E.g. Like most old people, he was fond of talking about old days.
(c) The distinctive function of intonation is apparent from the fact that communicatively different types of sentences are distinguished by intonation alone.
Compare:
It's no use sending for the doctor. – A categoric statement ( low fall in the nucleus).
It's no use sending for the doctor. – A non – categoric statement (low rise in the nucleus).
It's no use sending for the doctor? – A question (high rise in the nucleus).
It's no use sending for the doctor? – A statement + implication (fall – rise in the nucleus).
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* A non – final sense – group may also be delimited by the nuclear tone alone without any pause after it. In such case the delimitation of the sense – group from the following sense – group is achieved by a sudden "jump" from the end – pitch of the first nuclear tone to that of the head or the nuclear tone of the next sense – group, e.g. – There's a po liceman over there, go and ask him
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Wait here! – A categoric order (a falling tone)
Wait here! – A polite request
Isn't she a nice girl! – An exclamation (a falling tone)
Isn't she a nice girl? – A general question (a rising tone).
The decisive role of intonation in defining the communicative type of an utterance stands out clearly in those cases where grammar and intonation are at variance; for example, where the grammatical features suggest a statement but the intonation turns the utterance into a question, or vice versa, e.g. –
You like it?
Isn't he stupid!
(His pictures are very striking.) – Yes, aren't they?
(It looks like rain) – It does, doesn't it?
(d) Attitudinal meaning (the mood of the speaker, his attitude to the situation and to the listener) are also expressed only by intonation.
In his "Advice to Foreign Learners" A.C. Gimson emphasizes the necessity of learning "the English usage of falls and rises to signify the mood of the speaker, so that an over – use of rises will not give an unintentional impression of, for example, diffidence or complaint and too many falls create an unwitting effect of impolite assertiveness."