Form and function

A useful distinction in grammar is that of grammatical form and grammatical function. Grammatical form is concerned with the description of linguistic units in terms of what they are, and grammatical function is concerned with the description of what these linguistic units do. Note that we use capital letters at the beginning of function labels, but this is by no means standard practice everywhere.


Understanding the way that form and function relate to one another has important implications for text production and comprehension, and enables students to more accurately discuss how grammatical structure relates to meaning.

Here are the linguistic units relevant to the levels of form and function in a table. Hover over the labels with your cursor and click to see the full Glossary definition.

 Grammatical form labels Grammatical function labels

Word classes

  • noun, adjective, verb, adverb, determiner, pronoun, conjunction, preposition


  • noun phrase, adjective phrase, adverb phrase, preposition phrase


  • main clause, subordinate clause, relative clause







The terms Predicator and Modifier are not statutory in the National Curriculum, nor are the labels adjective phrase and adverb phrase. It may be useful to revisit the relevant pages on word classes, phrases, clauses and function labels if you need to.

Let's see how form-function operates in language. Consider the following sentence:

  • The plumber fixed the tap.

In this sentence the plumber is doing the fixing, and this phrase therefore functions as the grammatical Subject; whereas the tap is being fixed, which means that this noun phrase functions as the grammatical Object.

We can use a table to show the form/function interface more clearly:

FORM main clause
noun phrase   noun phrase
determiner noun verb determiner noun
  the plumber fixed the tap
FUNCTION Subject Predicator Object

It's important to be aware of the fact that the functional 'slots' of Subject, Object and Adverbial can typically be 'filled' by various different grammatical forms, as indicated in the table:

Grammatical function Grammatical form Example
Subject noun Sylvia loves doughnuts.
pronoun She is tired.
noun phrase The washing machine is broken.
Object noun Eva loves linguistics.
pronoun I want it.
noun phrase She smashed my new phone.
Adverbial adverb Suddenly, the elephants continued on their way.
adverb phrase Very suddenly, the elephants continued on their way.
preposition phrase In the morning, the elephants continued on their way.
noun phrase The next day, the elephants continued on their way.
subordinate clause When they had eaten, the elephants continued on their way.

You may think of other forms that can function as Subject and Object.

If you want to read more about form and function, have a look at these pages on Bas Aarts' blog:

In the activity, students are asked to work out the form and function labels of a list of given sentences.


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