Conjunctions form a closed class

There is a limited number of conjunctions and new ones cannot be added easily. Hence, like auxiliary verbs, numerals, determiners, pronouns and prepositions, conjunctions form a closed word class.

The function of conjunctions

These words conjoin, or add together, one element (phrases or clauses) with another. There are three types:

1. coordinating
2. subordinating
3. correlative

Coordinating conjunctions

Conjunctions such as and, but and or typically serve to add together two elements that are perceived to be of equal status. Consider the following utterance.

bread and butter

Here, the two elements bread and butter may be perceived to be equal, one is not subordinate to the other. The conjunction that coordinates these two elements is and. Similarly, the two elements my books and your CDs are also perceived to be on the same footing in the following utterance.

my books or your CDs

This time the conjunction or is used to coordinate the two elements. In contrast to the use of and, which implies addition, the conjunction or typically implies selectivity, i.e. one of the elements or the other, but not both. Further examples include the following.

knife and fork

not the knife but the fork

the man or the woman

The four coordinators in English are:

1. and
2. or
3. but
4. nor (though this last coordinator is used rarely in comparison to the first three)

Subordinating conjunctions

In contrast with coordinating conjunctions, conjunctions such as since, if, because, so, when, as, though, after, as, until, till, before and although subordinate one element to another, i.e. they often imply some sort of condition or contrast. Consider the following.

I’ll do it if you do it first

The second element of this utterance, you do it first, is subordinate to the first element, I’ll do it, as the conjunction if signals a condition, i.e. I will only carry out this action if, and only if, you carry out the action first. The following utterance provides a further example of a contrast between two elements.

I’m nervous though I think I can do it

The first element, I’m nervous, indicates the speaker’s psychological state, i.e. he or she is nervous. This state is contrasted with the subordinate second element, I think I can do it, which expresses another psychological state, i.e. the belief that he or she can carry out some particular action, despite the fact that he or she is nervous. Further examples of subordinating conjunctions include the following.

she can leave when she starts acting properly [condition]

they all cried since they had all loved the dog [contrast]

Graham will have to go now because the train is about to leave [condition]

Correlative conjunctions

Correlative conjunctions are pairs of words (a correlative conjunction and either an adjective or adverb) that work in tandem to link two phrases that are on the same footing. Examples include:

• either…or…
• neither…nor…
• both…and…
• not only…but also…
• whether…or…

Consider the following.

take either a blue one or a yellow one

Here, the correlative conjunction either…or… coordinates two noun phrases: (1) a blue one, and (2) a yellow one. Similarly, two noun phrases are linked in the following utterance.

both my father and my mother

Here noun phrase 1 (my father) is linked with noun phrase 2 (my mother) through the use of the correlative conjunction both…and…

Correlative conjunctions can also link so-called infinitive phrases. These are phrases that begin with the infinitive form of the verb (to + base form) and which may also incorporate various modifiers, e.g. to write a letter; to spend the money from your bank account. Consider the following.

I don’t know whether to laugh or to cry

Here, there are two infinitive phrases: (1) to laugh, and (2) to cry. They are coordinated with the correlative conjunction whether…or… Another example, using the correlative conjunction not only…but also… is:

not only to laugh long but also to live well