People speak and write in different ways on different occasions. There are, however, some words and structures which are mainly used in formal situations  – for example report writing, business meetings, conferences, polite conversations etc.

There are also some words and expressions which are mainly used in informal situations – conversations with friends etc.

In writing, we almost always use formal words and expressions. Speech, on the other hand, is often more informal.

Grammar

Some grammatical structures have two forms – formal and informal.

For example, in informal speech and writing we use contracted auxiliary verbs and negatives.

Formal: It is working.
Informal: It’s working.
Informal: He‘s gone.
Formal: He has gone.

Prepositions

In informal language prepositions often come at the end of certain structures.

Formal: To which nation does he belong?
Informal: Which nation does he belong to?

Some determiners are followed by singular verbs in formal language and plural verbs in informal language.

Formal: Neither of us likes him.
Informal: Neither of us like him.

Some pronouns have different forms in formal and informal language.

Formal: Whom did they elect?
Informal: Who did they elect?

In informal language we often leave out words.

Formal: She said that she would come.
Informal: She said she would come.
Formal: Have you seen Annie?
Informal: Seen Annie?

Vocabulary

Some words are mainly used in informal situations. In formal situations other words or expressions are used.

Informal                                               Formal
Fix                                                           Repair
Begin / start                                        commence
Thanks                                                   Thank you
What? / Pardon? / Sorry?              I beg your pardon?