The answer is: to eliminate dialect and slang.
A dictionary is a reference material in which one can find the meaning of words in a given language. Its purpose is to provide the objective sense of the language´s words, and however it may work to standardize a language, it is not one of its objectives to eliminate or impinge in any way on slang or dialects that deviate from the standard imposed by the it and other language institutions, both slang and dialects are recognized to have an independent existence that, as functions of languages, should strive.
