In systemic functional grammar

Systemic functional grammar

Systemic functional grammar , a component of systemic functional linguistics , is a form of grammatical description originally developed by Michael Halliday in a career spanning more than 50 years. It is part of a social semiotic approach to language called systemic-functional linguistics...

, a thematic equative is a thematic resource in which two or more separate elements in a clause are grouped together to form a single constituent of the theme-plus-rheme structure. An example of this is:

What the guests need for breakfast is an omelet.

Here, the theme—the grammatical point of departure—is in bold text; it announces at the start to the listener or reader what the message will be about—the writer's or speaker's angle ("I'm going to tell you what they need for breakfast"). The rheme (the rest of the clause) is in regular text. This type of clause sets up the theme-plus-rheme structure in the form of an equation, where theme = rheme. The equation is always expressed by some form of the verb be.

A thematic equative allows for all possible parts of a clause to be shifted to the start, to be the theme, so that the message can be structured in whatever way the speaker or writer wants. For example:

An omelet is what the guests need for breakfast. [I'm going to tell you something about an omelet.]

Many common expressions are what are known as marked thematic equatives; these expressions include those that start with "That's why ..." and "That's what ..." ("That's why you can't do it," "That's what I meant").

A unique feature of the thematic equative is its conveying of a meaning of exclusiveness in the rheme. In all of these examples, the meaning is that the only thing the guests need for breakfast is an omelet. This is in contrast with "The guests need an omelet for breakfast," which leaves open the possibility that they also need other things for breakfast.

See also

• Functional grammar
  Functional grammar
  Functional theories of grammar include a range of functionally based approaches to linguistics, the scientific study of language. The grammar model developed by Simon Dik bears this qualification in its name, functional grammar, as does Michael Halliday's systemic functional grammar.Role and...
  
  
• Michael Halliday
  Michael Halliday
  Michael Alexander Kirkwood Halliday is a British linguist who developed an internationally influential model of language, the systemic functional linguistic model. His grammatical descriptions go by the name of systemic functional grammar .-Biography:Halliday was born and raised in England...
  
  
• Nominal group
  Nominal group (language)
  In systemic functional grammar , a nominal group is a group of words which expresses an entity. A "nominal group" is widely regarded as synonymous to noun phrase in other grammatical models, although Halliday and some of his followers draw a theoretical distinction between the terms group and phrase...
  
  
• Systemic functional grammar
  Systemic functional grammar
  Systemic functional grammar , a component of systemic functional linguistics , is a form of grammatical description originally developed by Michael Halliday in a career spanning more than 50 years. It is part of a social semiotic approach to language called systemic-functional linguistics...