At the behest of the Linguistics, the Diglossia designates the coexistence of two or more different languages, which have a different range of use, in the same geographical area. One of these languages has what we could call prestigious status, since it is the language of official use, while the other will appear relegated to inferior social situations. In the event that there are three or more languages, the multiglossia or polyglossia.
Indeed, it will be possible to speak of diglossia when in a nation there is a specific use of an official language and another alternative language, which will be used in certain areas, for example, the first, which is the most formal, will be used in those contexts. in which formality and distance prevail, while the other, alternative and of relatively low variety with respect to the first, will be used mostly in informal contexts.
It should be noted that in a diglossia situation such as the one mentioned, it turns out to be inappropriate and even ridiculous to use both variants interchangeably, since the first can be learned formally in academic contexts, while the less formal, normally, is acquired as mother tongue.
Some issues that help to further differentiate the two languages indicate that the formal variety has grammatical categories that appear reduced or directly disappear in the less formal variant; the first has a cultured, specialized, technical, standardized lexicon, as a consequence of the elaboration of grammars, dictionaries, spelling rules, presence of literary body, on the other hand, in the second there is no such cultured lexicon, it has a vocabulary and expressions typical of popular and family environments and there is no standardization, much less literary heritage.
Examples of diglossia include French and Haitian Creole in Haiti and German with Swiss German in Switzerland, justly.
