I. FORMAL AND INFORMAL LANGUAGE

Most people speak and write in different ways on different occasions. In some languages, for example, there are very complicated rules about how to speak to older or more important people. English does not have a system of this kind. However, there are some words and structure which are mostly used in formal situations, when people are careful about how they express themselves: for example in official notices, business letters or reports, meeting or conferences, or polite conversation with strangers. And some words and structures are mostly used in informal situations: for example in conversations with friends, or letters to one's family. Writing is more often forma, and speech is more often informal, but informal writing and formal speech are used when the situation makes them preferable.

II. GRAMMAR

Some grammatical structures have different formal and informal versions. For example, contracted auxiliary verbs and negatives are common in informal speech and writing.

FORMAL: It has gone. It is not possible.

INFORMAL: It's gone. It isn't possible.

Prepositions come at the end of certain structures in informal language

FORMAL: In which century did he live?

INFORMAL: Which century did he live in?

Some relative structures are different.

FORMAL: The man whom she married ... .

INFORMAL: The man she married ... .

Some determiners are followed more often by singular verb forms in formal language, and by plural forms in informal language.

FORMAL: Neither of us likes him.

INFORMAL: Neither of us like him.

Subject and object forms of pronouns (e.g. I and me) are used differently in formal and informal language.

FORMAL: It was she who first saw what to do.

INFORMAL: It was her who first saw what to do.

FORMAL: Whom did the elect?

INFORMAL: Who did they elect?

Ellipsis (leaving out words) is more common in informal language.

FORMAL: Have you seen Mr. Andrews?

INFORMAL: Seen John?

FORMAL: We think that it is possible.

INFORMAL: We think it's possible.

III. VOCABULARY

Some words and expressions are used mainly in formal situations; in neutral or informal situations other words or expressions are used. And some words and expressions are only used in informal situations. Some examples.

- FORMAL: commense

- NEUTRAL/ INFORMMAL : begin/ start

- FORMAL: alight (from a bus or train)

- NEUTRAL/ INFORMMAL :get off

- FORMAL: I beg your pardon?

- NEUTRAL/ INFORMMAL :Pardon? Sorry? What? (Am.E Excuse me? Pardon me?)

- FORMAL: repair

- NEUTRAL/ INFORMMAL :mend (BrE), fix

- FORMAL: acceptable, satisfactory

- NEUTRAL/ INFORMMAL : All right, OK

- FORMAL: I am (very) grateful to you.

- NEUTRAL/ INFORMMAL : Thank you. Thanks

1. Had is sometimes dropped in very informal speech.

+ You had better go now. (formal)

+ You better go now. (informal)

+ I had better try again later. (formal)

+ I better try again later ( informal)

2. Help

Help can be followed by an object and infinitive with or without to - the structure with to is more common in an informal style.

+ To help s.o to do s.t (very formal)

+ To help s.o do s.t ( informal)

- Can somebody help me (to) find my ring?

- Help me (to) get him to bed.

+ It is also possible to use help without an object.

- Would you like to help peel the potatoes?

3. Tense.

Compare:

+ I look forward to seeing soon (FORMAL)

+ I am looking forward to seeing you soon. (LESS FORMAL)

+ Two and two is four. ( FORMAL)

+ Two and two are four ( INFORMAL)

 (Practical English Usage)