A text is meaningful because it is an actualization of the potential that constitutes the linguistic system; it is for this reason that the study of discourse (ʻtext linguisticsʼ) cannot properly be separated from the study of the grammar that lies behind it.
- Halliday (1985), Pag. 345

Now however it is necessary to argue the opposite case, and to insist on the importance of grammar in linguistic analysis. If I now appear as a champion of grammar, it is not because I have changed my mind on the issue, but because the issue has changed. The current preoccupation is with discourse analysis, or ʻtext linguisticsʼ; and it is sometimes assumed that this can be carried on without grammar – or even that it is somehow an alternative to grammar. But this is an illusion. A discourse analysis that is not based on grammar is not an analysis at all, but simply a running commentary on a text: either an appeal has to be made to some set of non-linguistic conventions, or to some linguistic features that are trivial enough to be accessible without a grammar, like the number of words per sentence (and even the objectivity of these is often illusory); or else the exercise remains a private one in which one explanation is as good or as bad as another [...] Thus the present interest in discourse analysis is in fact providing a context within which grammar has a central place.
- Halliday (1985), Pag. XVI-XVII