All the structural analyses could be reinterpreted in terms of the features selected [...] The analysis covers the clause, in its textual [...] interpersonal [...] and ideational [...] aspects; primary classes of group and phrase [...] and the clause complex [...] there are also brief treatments of cohesion [...] and grammatical metaphor [...] The description incorporates certain features of the spoken language, not only because of the importance of spoken texts but also because a framework that does not accomodate the special properties of speech is presenting an impoverished view of the system.
- Halliday (1985), Pag. XXVII