Intonation plays a very important role in English speech. Intonation serves to form sentences and intonation-groups, to define their communicative type and to express the speaker's thoughts.
There are four communicative types of sentences:
1. Statements,e.g. I like music.
2. Questions,e.g. Can you prove it? How old are you?
3. Imperative sentences or commands,e.g. Try it again.
4. Exclamations,e.g. Sweet of you!
Long sentences, simple extended, compound and complex, are subdivided into intonation-groups(or syntagms).Each syntagm is characterized by a certain intonation pattern.Intonation patterns consist of one or more syllables and several unstressed ones. They have the following parts: the pre-head, the head, the nucleus and the tail.
The pre-headincludes unstressed and half-stressed syllables preceding the first stressed syllable.
The headincludes the stressed and unstressed syllables beginning with the first stressed syllable up to the last stressed syllable.
The last stressed syllable is called the nucleus.
The unstressed and half-stressed syllables that follow the nucleus are called the tail.
e.g. It was a very sunny day yesterday.
It was athe pre-head.
... very sunnythe head.
... daythe nucleus.
... yesterday- the tail.
The rises and falls that take place in the nucleus are called nuclear tones.So there are two most frequently used types of the nuclear tone: Low Falland Low Rise.
The falling nuclear tone shows that the intonation-group is complete and important by itself. When used with the non-final intonation-group it shows that this non-final intonation-group is not closely connected with the following one.
e.g. I'll tell him all when he comes.
The rising nuclear tone shows that the non-final intonation-group is closely connected in the meaning with the following intonation-group, is not important by itself and implies continuation.
e.g. Generally speaking, I prefer tennis.
In English notional words (nouns, adjectives, verbs, etc.) are generally stressed.
Auxiliary verbs, articles, prepositions and most pronouns are usually unstressed. But any part of speech may be stressed if it is semantical ly important.
e.g. What is he going to do?