1. Formal and informal styles
How to use?

2. Formal language
may be used, for example, at official functions, and in debates and ceremonies.

3. Formal language is characterised by the following features:
complex sentences
use of reported speech
indirect questions
use of modals such as could and would rather than can and will
full forms (should not) instead of contractions (shouldn’t)
frequent use of the passive voice
limited use of phrasal verbs
frequent use of long words with Latin or Greek roots

4. Formal writing is probably the most difficult type of writing
Formal writing is probably the most difficult type of writing. It is impersonal, meaning it is not written for a specific person and is written without emotion.
Some kinds of writing are always written in formal English. Formal writing includes:
Business Letters
Letters of complaint
Some essays
Reports
Official speeches
Announcements
Professional s

5. Neutral language
is used with non-emotional topics and information.

6. Neutral language is characterised by:
simpler sentences
active rather than passive voice
factual rather than emotional language
limited use of complex language
limited use of slang

7. Neutral writing is not necessarily formal or informal
Neutral writing is not necessarily formal or informal. It is not usually positive or negative. A neutral register is used to deliver facts. 
Some writings are written in a neutral register. This means they are not specifically formal or informal.  Writing in the natural language register includes:
Reviews
Articles
Some letters
Some essays
Technical writing

8. Informal language
is used in informal situations with friends, fellow workers, and members of the family.

9. Informal language is characterised by:
simple, often grammatically incomplete, sentences
active voice
emotional language
personal opinions
humour
slang, idioms and cliches
phrasal verbs
exclamations

10. Informal writing is written in the way we talk to our friends and family. We use informal writing when we are writing to someone we know very well.
Some kinds of writing can be written in an informal style. Informal writing includes:
Personal s
Short notes
Friendly letters
Most blogs
Diaries and journals
Phone texts

11. THANK YOU FOR YOUR ATTENTION!