© 2019 Steve Campsall

word classes: 'parts of speech'

We've looked at phrases and seen how they act to build up sentences; and we've also met the noun phrase (a phrase with a noun as its head word). There are several other possible grammatical functions for the head word of a phrase. These functions are referred to as word classes. Here they are:

Part of Speech



A noun is a word that can occupy various grammatical positions within a sentence.

Nouns label things: either real things in the world (e.g. 'cat' - a concrete noun); imaginary things (e.g. 'ghost' - still called a concrete noun); things that exist in the realm of ideas (e.g. 'love' - called an abstract noun); and things that are individually given names (e.g. 'Steve', 'Eiffel Tower' - called proper nouns).

  • Nouns are said to be from an open class of words. This means that more nouns are being added all the time as new things need naming.

A noun can take the grammatical position in a noun phrase that is occupied by its head word.

Within a sentence, nouns or noun phrases can occupy three possible grammatical positions and each of these has a different grammatical function.

  • It can be placed before a verb to tell what or who is carrying out the action told of by the verb. This position is called the subject position (e.g. The cat ate the mouse).

  • Some types of verb require a noun or noun phrase to follow them. This noun is then said to be in the object position and it tells what or who  was affected by the action of the verb (The cat ate the mouse).

  • Finally - and very frequently - a noun or noun phrase can follow a preposition (see below) to form a prepositional phrase.


A pronoun is similar to a noun (indeed its function is often to replace a noun). Pronouns occupy the grammatical space for the subject or the object in a clause or sentence.

  • Note that, unlike nouns, the form of a pronoun changes whether it is occupying the subject (e.g. he) or object (e.g. him) position.

Pronouns are often used to save the need to repeat a noun word which is then called its antecedent or referent, e.g. The tiger crawled through the jungle where it couldn't be heard'. In this case, the pronoun 'it' has, as its antecedent - its referent - the noun 'tiger'.

  • Pronouns form a closed class of words. This means that no more pronouns are required for the language to be complete.


Adjectives are usually associated with a noun which they act to modify in a noun phrase. Their grammatical position is often to precede (i.e. pre-modify) their noun, e.g. the black cat.

Adjectives can also occupy a position following a link or copula verb (e.g. verbs that link a subject with a word or phrase that tells more about the subject, e.g. be, is, am, seem, appear). Both nouns and adjectives can fill this grammatical position, a position referred to as the grammatical complement, e.g. 'The man is tall.' and 'They are pandas'.

  • Adjectives form an open class of words.

These are a separate, small group of modifiers. A determiner is a word that functions to pre-modify and specify a particular noun, e.g. the, a, some, many, those, these.


Adverbs are unusual in that they can be moved around a sentence and still retain their meaning. Rather like an adjective, an adverb acts as a modifier. Adjectives modify nouns and adverbs modify verbs, other adverbs, adjectives or whole sentences.

  • Modifying a verb: 'He ran quickly'

  • ...a sentence: 'Thankfully, they have all managed to escape'

  • ...an adjective: 'He is really old'; 'The most expensive watch has been lost.'

  • ...another adverb: 'It is simply too expensive'

  • ...a prepositional phrase: 'He is almost at the top'.

Adverbs often occur as a part of a phrase, often one introduced by a preposition, to form an adverbial phrase. These phrases function to add extra information, quite often to the verb in a sentence (see also preposition below):

He walked in a most peculiar way.

Adverbial phrases often give detail about place, time, manner or cause (i.e. they tell where, when or how an action occurs), e.g. 'He will arrive in the hall at four o'clock no doubt looking lost.'

  • Adverbs form an open class of words.


Verbs are an important word class. If they occur with a noun or noun phrase they make the verb finite and act as its subject.

Verbs tell of doing (action) or being

In a typical sentence, a verb follows a subject (SV) or a complement (SC) and precedes any object (SVO), e.g. 'The cat (S) ate (V) the mouse (O)'.

There are other grammatical positions for verbs; however in these positions, the verb is not part of a subject-verb unit and is, therefore, not finite: they are called non-finite.

  • For example, non-finite forms of verbs can act as a noun and be the subject or object of another finite verb, e.g. 'Cooking is fun'; 'To swim can help overall fitness'; 'He enjoys running.

  • Non-finite verb forms can function as an adjective to modify a noun, e.g. 'Mix the cooked apples with a little melted sugar'.

  • Main verbs can use an auxiliary verb to help them form a verb phrase, e.g. 'I was doing my homework.'

  • Verbs form an open class of words.


Conjunctions link words, phrases and clauses to create larger grammatical units.

Co-ordinating conjunctions link equal units. These are the words 'and', 'but' and 'or'.

Subordinating conjunctions, e.g. however, although, when, because form a dependent clause that adds detail to a main clause, e.g. He bought the phone even though he knew it was stolen.'

  • Conjunctions are a closed class of words


These mainly small words link to a noun or noun phrase to create a prepositional phrase that functions to relate two aspects of the sentence and give information about place, time or manner, e.g. 'He is in the room'; 'She sings with a fine voice'.

Prepositional phrases often function as adverbial phrases but can function adjectivally to add detail to a noun by post-modifying it, e.g. ' The man with the wonky nose'.

  • Prepositions form a closed class of words.


Interjections are used to suggest sudden emotional outbursts, e.g. 'Ouch!', 'Hey!'

  • Interjections form an open class of words.