This grammar gives emphasis to the view from above.

For Halliday, grammar is described as systems not as rules, on the basis that every grammatical structure involves a choice from a describable set of options. Language is thus a meaning potential. Grammarians in SF tradition use system networks to map the available options in a language. In relation to English, for instance, Halliday has described systems such as mood, agency, theme, etc. Halliday describes grammatical systems as closed, i.e.