Determiners are a kind of noun modifier; they precede and are necessarily followed by nouns. While adjectives perform a similar function, the term ‘determiner’ refers to a relatively limited set of well-established words that can be said to ‘mark’ nouns.
The function of determiners is to ‘express reference’; i.e. they clarify what a noun is referring to. For example when one says ‘that box’, the listener knows which box is being referred to.
There are many types of determiners:
There are three articles: a, an, and the.
A and an are indefinite articles that serve the same purpose, but they cannot be used interchangeably, because ‘a’ is only used before words that begin with consonants, and ‘an’ is used only before words that begin with vowels. (Note: ‘an’ before ‘h’ when it is silent, as in ‘hour’ and ‘honour’; ‘a’ before ‘u’ and ‘eu’ when they sound like ‘you’, as in ‘European’ and ‘university’.
The uses of the indefinite article are as follows:
To refer to some member of a group, class or category. For example He is a doctor (profession)/an Indian (nationality)/a Hindu (religion).
To refer to a kind of, or example of something. For example He has a large nose/a thick beard/a strange aunt.
Preceding singular nouns, with the words ‘what’ and ‘such’. For example What a car! Oh, that’s such a shame!
To mean ‘one’ object, whether a person or thing. For example The thieves stole a necklace and a portrait.
To refer to something that is being mentioned for the first time. For example There was a chill in the air.
We usually say a hundred, a thousand, a million, etc.
‘A’ is not indiscriminately used to refer to singular objects; ‘one’ is used when emphasis is required. For example There is only one way out of this mess.
‘The’ is known as the definite article in English. Its uses are as follows:
When something is being referred to that has already been mentioned. For example I saw a pretty girl at the mall today. The pretty girl did not, however, see me.
When both parties involved in the conversation are aware of what is being discussed. For example Where is the restroom?
To refer to unique objects. For example the sun, the moon, the Earth, the Taj Mahal.
With superlatives and ordinal numbers (numbers used to rank a set of objects). For example Mt Everest is the tallest mountain on earth, Neil Armstrong was the first man on the moon.
To refer to groups of people, geographical areas and oceans, and with decades or groups of years. For example the Americans, the Sahara/Pacific, the fifties/sixities/seventies/eighties.
See article on Quantifiers.
This, that, these and those are known are demonstratives; they describe the position of an object, seen from the speaker’s viewpoint.
This and these (used for singular and plural nouns respectively) refer to objects that close by. For example Whose car is this? Whose cars are these?
That and those (used for singular and plural nouns respectively) refer to objects that are further away. The closeness can be physical or psychological. For example Who lives in that house?
Numbers are cardinal (one, two, three, etc) and ordinal (first, second, third, etc). Cardinal numbers are adjectives that indicate quantity (There are fives apples on the table), and ordinal numbers indicate rank or order (This is the first time for me on a plane).
The words all, both, half, each, every, either and neither are known as distributives.
All, Both, Half
These three words can be used in the following ways:
Don Bradman is the greatest batsman of all time.
‘the’ + uncountable noun/countable noun in plural form
We have all the time in the world.
All the people in the hall went quiet.
‘my’, ‘your’, etc + uncountable noun/countable noun in plural form
All my life I have been waiting for this moment.
All you friends have been invited to the party.
‘this’, ‘that’ + uncountable noun/‘these’, ‘those’ + countable noun in plural form
Look at all this dust!
I do not have time for all these formalities.
‘the’ /‘my’, ‘your’, etc/‘these’, ‘those’ + countable noun in plural form (note: used only when two objects are being referred to)
Both the dogs have passed away.
Both my ankles have been hurting since I jumped from the balcony.
Both these books must be returned within the week.
‘a’ + uncountable noun
We bought half a kilo of rice.
‘the’/‘my’, ‘your’, etc/‘this’, ‘that’, ‘these’, ‘those’ + noun
Half the village perished in the floods.
I spent half my inheritance on travelling the world.
You may have half (of) this cake.
Only half (of) those points are relevant.
Each, Every, Either, Neither
Possessive pronouns and adjectives indicate who an object belongs to.
The pronouns are
mine (first person: This car is mine = I own this car)
yours (second person: This car is yours = You own this car)
his, hers, and its (third person: This cars is his/hers = He/she owns this car).
The corresponding adjectives are
his, her, and it
Other and another are ‘difference words’; they refer to something different, or remaining, or more. Other is used with singular and plural nouns, while another is used strictly with singular nouns.
What other colours can I get this in?
Is there another colour that this is available in?
Which and whose are ‘defining words’; they indicate which thing or person is being referred to.
This is the house which I used to live in as a child.
This is the man whose window you broke.
See the article on question words