What makes me to discuss these professional terms? Because they are useful which were overlooked by most of us. Beside, a great book always has its impressive impacts on all of us, this thought just right up my mind after I have read a book written by Mr. Yi Zinan, which is another reason for sharing linguistics terms with you.
This time I am going to discuss 2 terms – discourse（话语）or text（语篇）. Actually, people outside linguistic field might not be familiar with these two words. Thus, there is a need to explain these words.
Traditionally, when we study a language, the points are always on sentences. In fact, sentences are the original and traditional objects, though, outside the areas of sentences are extremely huge, linguistics still pay less attention on them.
Sentences are easy to understand as a basic unit, since they have obvious outer-forms – the beginning of a sentence is written by a uppercase letter and a full stop marks the end a sentence. In this way, a person can tell whether a couple of words form a sentence, even his do not understand its meaning.
In fact, there are some features that outside the field of sentences, thus linguists are starting to study the field which is beyond sentence. Therefore, discourse（话语）and text（语篇）have come into being which are based on the meaning of a sentence since sentences all have a fixed form.
Then what is the difference between discourse and text. Linguists have given them a wide meaning, which have arisen different definitions about these terms. Here, I would like to give a general definition: “A text, or discourse, is a stretch of language that may be longer than one sentence.” However, someone give them a specific definition purely from their semantics, for example, Halliday said “A text is the production of ongoing semantic relationships.”
If we look it from the view of Halliday, any oral, formal words from a paragraph, regardless of their length, will be a discourse or text as long as it has a complete semantics. Thus, “Help!” which scream out under emergency situations can also be a discourse or text.
In terms of discourse, there are several areas that we can spread over. But coherence（连贯）and cohesion（衔接）are discussed mostly. These really determine whether a paragraph is influent and can be easily read.