Pronouns are used to substitute for nouns. They are not a requirement of a sentence, and it is possible for them to never to be used in sentences. However, they are useful because sentences look silly without them. For example, the sentence:

• Alistair is doing what Alistair thinks is best for Alistair's right as a human being.

There are no pronouns in that above sentence, and as such, it looks silly. Pronouns are words like "I, me, you, he, she, they, it." For example:

• You are silly.
• I am not silly.
• He is not silly.
• We are not silly.
• They are silly.

They allow sentences to be easier to understand.

• There are different types of pronouns:
  • First person pronouns
  • Second person pronouns
  • Third person pronouns.

• Pronouns change depending on what part of the sentence they replace. They can be the subject (the person or thing doing the action described), the object (anyone or anything that isn't the subject), and they can be used to mark ownership or possession.

• Pronouns also change depending on whether they refer to one person or thing (singular) or a group of people or things (plural).

• First person pronouns are used when referring to oneself, for example:
  • I think I am not silly.
  • Singular. As a subject, I (this is always a capital letter). As an object, me. As a possessive, my.
  • Plural. As a subject, we. As an object, us. As a possessive, our.

• Second person pronouns are used to refer to someone who you are conversing with, the person the sentence is intended to be heard by. For example:
  • You are not very silly.
  • Second person singular is not commonly used in modern English. Use a plural form always. As a subject or an object, you. As a possessive, your.

• Third person pronouns are used when referring to something else that is outside the conversation, either some other person, or an object not capable of understanding or communicating. For example:
  • I don't like the tree because it is mean to me.
  • I don't like the RIAA because they sue me.
  • Third person singular pronouns are the only pronouns marked for gender. If gender is unknown, use 'he or she' or use a plural. Never use the neuter pronouns to refer to people, because it is considered rude. In English, unlike many languages, gender is usually only used to describe things that have a definite gender, like people or cats.
  • Singular (in form masculine/feminine/neuter). As a subject, he/she/it. As an object, him/her/it. As a possessive, his/her/its.
  • Plural. As a subject, they. As an object, them. As a possessive, their.

A Pronoun is a word used in stead of a noun: as, The boy loves his book; he has long lessons, and he learns them well.

The pronouns in our language are twenty-four; and their variations are thirty-two: so that the number of words of this class, is fifty-six.

Pronouns are divided into three classes; personal, relative, and interrogative.

A personal pronoun is a pronoun that shows, by its form, of what person it is; as,

"Whether it were I or they, so we preach, and so ye believed."--1 Cor., xv, 11.

The simple personal pronouns are five: namely, I, of the first person; thou, of the second person; he, she, and it, of the third person.

The compound personal pronouns are also five: namely, myself, of the first person; thyself, of the second person; himself, herself, and itself, of the third person.

A relative pronoun is a pronoun that represents an antecedent word or phrase, and connects different clauses of a sentence; as,

"No people can be great, who have ceased to be virtuous."--Dr. Johnson.

The relative pronouns are who, which, what, that, as, and the compounds whoever or whosoever, whichever or whichsoever, whatever or whatsoever.

What is a kind of double relative, equivalent to that which or those which; and is to be parsed, first as antecedent, and then as relative: as,

"This is what I wanted; that is to say, the thing which I wanted."--L. Murray. III.

An interrogative pronoun is a pronoun with which a question is asked; as, "Who touched my clothes?"--Mark, v, 30.

The interrogative pronouns are who, which, and what; being the same in form as relatives.

Who demands a person's name; which, that a person or thing be distinguished from others; what, the name of a thing, or a person's occupation and character.

Pronouns have the same modifications as nouns; namely, Persons, Numbers, Genders, and Cases. Definitions universally applicable have already been given of all these things; it is therefore unnecessary to define them again in this place.

The declension of a pronoun is a regular arrangement of its numbers and cases.

Simple personals.

The simple personal pronouns are thus declined:--

I, of the FIRST PERSON, any of the genders.

Sing. Nom.  I,             Plur. Nom.  we,
      Poss. my, or mine,         Poss. our, or ours,
      Obj.  me;                  Obj.  us.

YOU, of the SECOND PERSON, any of the genders.

Plur. Nom.  you,
      Poss. your, or yours,
      Obj.  you.

HE, of the THIRD PERSON, masculine gender.

Sing. Nom.  he,            Plur. Nom.  they,
      Poss. his,                 Poss. their, or theirs,
      Obj.  him;                 Obj.  them.

SHE, of the THIRD PERSON, feminine gender.

Sing. Nom.  she,           Plur. Nom.  they,
      Poss. her, or hers,        Poss. their, or theirs,
      Obj.  her;                 Obj.  them.

IT, of the THIRD PERSON, neuter gender.

Sing. Nom,  it,            Plur. Nom.  they,
      Poss. its,                 Poss. their, or theirs,
      Obj.  it;                  Obj.  them.

Compound personals.

The word self, added to the simple personal pronouns, forms the class of compound personal pronouns; which are used when an action reverts upon the agent, and also when some persons are to be distinguished from others: as, sing, myself, plur. ourselves; sing, thyself, plur. yourselves; sing, himself, plur. themselves; sing, herself, plur. themselves; sing, itself, plur. themselves. They all want the possessive case, and are alike in the nominative and objective. Thus:--

MYSELF, of the FIRST PERSON, any of the genders.

Sing. Nom.  myself,   Plur. Nom.  ourselves,
      Poss. ------,         Poss. ---------,
      Obj.  myself;         Obj.  ourselves.

YOURSELF, of the SECOND PERSON, any of the genders.

Plur. Nom.  yourselves,
      Poss. ----------,
      Obj.  yourselves.

HIMSELF, of the THIRD PERSON, masculine gender.

Sing. Nom.  himself,  Plur. Nom.  themselves,
      Poss. -------,        Poss. ----------,
      Obj.  himself;        Obj. themselves.

HERSELF, of the THIRD PERSON, feminine gender.

Sing. Nom.  herself   Plur. Nom.  themselves,
      Poss. -------,        Poss. ----------,
      Obj.  herself;        Obj.  themselves.

ITSELF, of the THIRD PERSON, neuter gender.

Sing. Nom.  itself,   Plur. Nom.  themselves,
      Poss. ------,         Poss. ----------,
      Obj.  itself;         Obj.  themselves.

Relatives and interrogatives.

The relative and the interrogative pronouns are thus declined:--

WHO, literally applied to persons only.

Sing. Nom.  who,      Plur. Nom.  who,
      Poss. whose,          Poss. whose,
      Obj.  whom;           Obj.  whom.

WHICH, applied to animals and things.

Sing. Nom.  which,    Plur. Nom.  which,
      Poss. ----,           Poss. -----,
      Obj.  which;          Obj.  which.

WHAT, applied ordinarily to things only.

Sing. Nom.  what,     Plur. Nom.  what,
      Poss. ----,           Poss. ----,
      Obj.  what;           Obj.  what.

THAT, applied to persons, animals, and things.

Sing. Nom.  that,     Plur. Nom.  that,
      Poss. ----,           Poss. ----,
      Obj.  that;           Obj.  that.

AS, applied to persons, animals, and things.

Sing. Nom.     as,    Plur. Nom.  as,
      Poss.    ----,        Poss. ----,
      Obj.     as;          Obj.  as.

Compound relatives.

The compound relative pronouns, whoever or whosoever, whichever or whichsoever, and whatever or whatsoever are declined in the same manner as the simples, who which, what. Thus:--

WHOEVER or WHOSOEVER, applied only to persons.

Sing. Nom.  whoever,     Plur. Nom.  whoever,
      Poss. whosever,          Poss. whosever,
      Obj.  whomever;          Obj.  whomever.

Sing. Nom.  whosoever,   Plur. Nom.  whosoever,
      Poss. whosesoever,       Poss. whosesoever,
      Obj.  whomsoever;        Obj.  whomsoever.

WHICHEVER or WHICHSOEVER, applied to persons,
animals, and things.

Sing. Nom.  whichever,   Plur. Nom.  whichever,
      Poss. ---------,         Poss. --------,
      Obj.  whichever;         Obj.  whichever.

Sing. Nom.  whichsoever, Plur. Nom.  whichsoever,
      Poss. ---------,         Poss. --------,
      Obj.  whichsoever;       Obj.  whichsoever.

WHATEVER or WHATSOEVER, applied ordinarily to 
things only.

Sing. Nom.  whatever,    Plur. Nom.  whatever,
      Poss. --------,          Poss. --------,
      Obj.  whatever;          Obj.  whatever.

Sing. Nom.  whatsoever,  Plur. Nom.  whatsoever,
      Poss. ---------,         Poss. --------,
      Obj.  whatsoever;        Obj.  whatsoever.

Ya'll

The pronoun ya'll, or y'all is a contraction of "you all". It is traditionally used in the south of the United States, where in the north you all is more common. Ya'll follows the same conjugation rules as they.

A part of the text in this article, was taken from the public domain English grammar "The Grammar of English Grammars" (http://www.gutenberg.net/etext/11615) by Goold Brown, 1851.