Pronoun

A pronoun is traditionally called a part of speech in grammar (but many modern linguists, experts in linguistics, call it a special type of noun[1]) In English, pronouns are words such asme, she, his, them, herself, each other, it, what.
Pronouns are often used to take the place of a noun, when that noun is understood (has already been named), to avoid repeating it. For example, instead of saying
Tom has a new dog. Tom has named the dog Max and Tom lets the dog sleep by Tom's bed.
it is easier to say

Tom has a new dog. He has named it Max and he lets it sleep by his bed.
When a pronoun replaces a noun, the noun is called the antecedent. But, there are times when the pronoun has no antecedent. This is because generally, the antecedent (what comes before) refers grammatically to the use of the relative pronoun in particular. For example, in the sentence: The dog that was walking down the street, the relative pronoun is the word thatreferring back to the antecedent, the word 'dog'. In the sentence The spy who loved me, the relative pronoun is the word 'who' and its antecedent is the word 'spy'.

Differences and similarities to nouns

Pronouns are different from common nouns because they normally can't come after articles or other determiners. (For example, people don't say "the it".) Pronouns also rarely come afteradjectives. They are also different because many of them change depending on how they are used. For example, "we" is a 'subject' in grammar, but the word changes to us when used as an object.
Pronouns are the same as nouns because they both change for number (singular & plural), case (subject, object, possessive, etc.), and gender (male, female, animate, inanimate, etc.) Nouns and pronouns can be used in almost all the same places in sentences, and they name the same kinds of things: people, objects, etc. Even though they can't normally come after determiners, or adjectives, neither can proper nouns.

Kinds of pronouns

There are four kinds of pronouns: personal, reciprocal, interrogative, and relative.
Kinds of English pronouns
i
personal
you love them
Your sister loves herself
ii
reciprocal
we like each other
we are looking at one another
iii
interrogative
who is there?
what happened?
iv
relative
the person who saw it
the time which you told me

Personal pronouns in English
This table shows all the personal pronouns in English that are commonly used today.
Personal pronouns in English
Singular
Plural
Subject
Object
Possessive
Subject
Object
Possessive
First
I
me
mine
we
us
ours
Second
you
you
yours
you
you
yours
Third
Feminine
she
her
hers
they
them
theirs
Masculine
he
him
his
Neuter
it
it
its
A Subject Pronoun can replace a noun that is the subject of a sentence. Refer to the table above; the subject pronouns are: I, You, He, She, It, We, They.
Another type of personal pronoun is called the 'reflexive pronoun'. Reflexive pronouns are the words ending in '-self' or '-selves', such as: myself, itself, themselves.