English belongs to tone language, and all English words show different meanings along with different intonation. The melody of English is the most beautiful part when we speak it. During the daily learning, what we pay attention to is English pronunciation, and we always omit English intonation. However, intonation means the world to verbal communication. Different tones in the same sentences may change the basic meanings of these sentences. However, when we study English at first, we study the words and phrase instead of tones. This leads to a bad situation that we can understand the meaning of book, but we can not express it correctly. This is the worst situation we Chinese students face now. The aim in this paper is to discuss some central issues directly concerned with the functions of intonation in English, among which the role it plays in discourse is not the least important.
This paper consists of five parts. The first part is the introduction of the significance of intonation. The second part is the definition of intonation. In part three, the author presents and analysis the basic features of English intonation. The fourth part is the analysis of functions of intonation in verbal communication. And the last part is the conclusion.

II. The Definition of Intonation

   Intonation is the melody of speech. In studying intonation we study how the pitch of the voice rises and falls, and how speakers use this pitch variation to convey linguistic and pragmatic meaning. It also involves the study of the rhythm of speech, and the study of how the interplay of accented, stressed and unstressed syllables functions as a framework onto which the intonation patterns are attached (Cruttenden 285).
In book Teaching Pronunciation: A Reference for Teachers of English to Speakers of Other Languages, the author Celce Murcia gives English intonation a definition like this: intonation is the variation of pitch while speaking which is not used to distinguish words. It contrasts with tone, in which pitch variation does distinguish words (367). Intonation, rhythm, and stress are the three main elements of linguistic prosody. Intonation patterns in some languages, such as Swedish and Swiss German, can lead to conspicuous fluctuations in pitch, giving speech a sing-song quality.
For some linguists the term intonation covers not only pitch, but also stress and pause phenomena on a suprasegmental level. For others, though, intonation refers exclusively to the contrasts caused by pitch and its various shifting tunes.
Needless to say, there is little consensus of opinion among linguists on which aspects of the fundamental frequency line should be considered most significantly. But important to grammar as intonation may be, it clearly stands apart in several ways. To start with, as the famous linguist Bolinger has reminded us, it is concerned with speakers and hearers as well as their significant utterances, which means already a departure from the rigour and consistence of abstract grammatical structures (126).
    If there is no intonation in English, our speech would be in the literal sense of the word, monotonous. Either it would all remain on one pitch throughout, or every utterance would employ exactly the same stereotyped tune at all times. But speakers do neither of those things: they make the pitch of their voice rise, fall, jump and swoop, in all sorts of different ways. Even the most boring speaker has access to a considerable repertoire of tunes (intonation patterns)—though maybe some speakers are better than others at exploiting this. Lively speakers typically make good use of the wide repertoire of possible intonation patterns that English offers. This is true both for the broadcaster, lecturer, preacher, politician, or businessman addressing a public audience and for the participant in an ordinary everyday conversational interchange or informal chat. 浅析英语语调在口语交际中的功能(2):http://www.youerw.com/yingyu/lunwen_35647.html