When these political variation, cultural and educational needs require a national standard usually the language of the capital city, which is adapted as a national standard language.
Dictionaries are in fact one of the most important devices to standardize the language.
This occurs by creating a standard in meaning and usage. So a dictionary is socially the mirror of its society. All socially accepted conventions or refused ones can be derived from the content of the dictionaries. The variety and number of English dictionaries has grown rapidly especially in United Kingdom. The most well-known publishers are Chambers, Collins, Longman, Cambridge and Oxford University Press.