Introduce informal language and when it is used in English composition with regard to the audience.
Introduce formal language, when it is used in English composition with regard to audience, and how to convert common informal words or phrases into more formal constructions.
This packet should help a learner seeking to understand English writing style and who is confused about how to write with the appropriate level of formality. It will explain the difference between formal and informal language.
The following websites provide good information on using appropriate language:
Avoiding Cliches
http://www.westegg.com/cliche/
Avoiding Idioms:
http://www.idiomconnection.com/
Avoiding Slang (with practice sentences):
http://www.burlington.mec.edu/~grammar/FOV1-0001D416/?OpenItemURL=S00D4879B
Formal Language (with practice sentences):
http://www.monash.edu.au/lls/llonline/writing/general/academic/3.1.xml
Source: see above