Lexicography usually distinguish the general dictionaries of special. Those are intended to describe the full lexicon of a language; these only a certain sector. Among the special, it is convenient to distinguish the integrals of the differential. Integral one, the articles explain the words are given special lexicon, the Spanish spoken in Mexico, for example, but without intending to oppose it to another, spoken in Argentina, either by case. A comprehensive dictionary of Mexican Spanish contains, therefore, many voices are also part of the comprehensive lexicon spoken in Argentina, to continue the example. In contrast, in a differential dictionary words and proper to a specific geographical, social or historical dialect, in order to oppose them to other designations characteristics of some other group of speakers meanings is. Be prepared for the Mexican Academy of Language dictionary, is, first, special and other differential. This means that who see it find voices and definitions if not exactly unique, yes own Mexican Spanish. Obviously, this can not be taken strictly. Perhaps sufficient to note that the words and meanings contained in this dictionary, first, are employed or at least known to a large part of Mexican Spanish speakers and, secondly, not used or known by most no Spanish-speaking Mexicans.