Diglossia

In linguistics, diglossia is where two dialects or languages are used by a single language community. In addition to the community's everyday or vernacular language variety, a second, highly codified lect is used in certain situations such as literature, formal education, or other specific settings, but not used normally for ordinary conversation. The H variety may have no native speakers within the community. In cases of three dialects, the term triglossia is used. When referring to two writing systems coexisting for a single language, the term digraphia is used.