In English, the indefinite pronouns are:

Singular:

• one
  one someone anyone no one everyone
• each
  each somebody anybody nobody everybody
• either or neither
  (n)either something anything nothing everything

Examples:

• Somebody is coming to dinner.
• Neither of us believes a word Harry says.

Plural:

Examples:

• Both are expected at the airport at the same time.
• Several have suggested canceling the meeting.

Singular with noncountables / Plural with countables:

Examples:

• Some of the dirt has become a permanent part of the rug.
• Some of the trees have been weakened by the storm.

Indefinite pronouns use apostrophes to indicate possessive case:

Examples:

• The accident is nobody’s fault.
• How will the roadwork affect one's daily commute?

Some indefinite pronouns may also be used as determiners.

one, each, either, neither, some, any, one, all, both, few, several, many, most

Note the differences:

• Each person has a chance.

  (Eachis a determiner describing person.)

• Each has a chance.

  (Each is an indefinite pronoun replacing a noun.)

• Both lawyers pled their cases well.

  (Both is a determiner describing lawyers.)

• Both were in the room.

  (Both is an indefinite pronoun replacing a noun.)

Indefinite pronouns—words like anybody, anything, somebody, something, everybody, everything, neither, none, each, either—refer to unspecified people or things. Although they can seem to refer to more than one person or thing, most take singular pronouns. A few, however, can be used with either singular or plural pronouns. Here's how to determine which pronoun, singular or plural, to use:

Does the indefinite pronoun contain an explicit reference to one or more than one person or thing? If it ends in any of the singular constructions -thing, -body, and --one, it refers to one person or thing and takes a singular pronoun. Though less explicit, each and none (meaning each one and no one) also refer to a single person or thing and take a singular pronoun.

A few indefinite pronouns are more ambiguous. All, any, more, most, neither, and some refer sometimes to one, sometimes to more than one person or thing. For that reason, each can take either singular or plural pronouns, depending on the context. If you're referring to several people or things within a unit, use a plural pronoun.

• All in the regiment advanced until they reached the beach.

If you're referring to the unit as a whole—as a group rather than as several individuals—use a singular pronoun.

• All of the regiment advanced until it reached the beach.

Remember: Most indefinite pronouns refer to one person or thing and take a singular pronoun. To determine whether to use singular or plural pronouns with ambiguous indefinite pronouns, examine the context of the sentence.

The Indefinite Pronouns algo and nada followed by an adjective, generally (but not necessarily) take de before the adjective, as:

• Tengo algo (de) bueno: I have something good.
• No tengo nada (de) bueno: I have nothing good.

Un nada is used as a noun, as:

• Un nada le asusta: A nothing frightens him.

La nada--nothingness.