Diglossia

In linguistics, diglossia (/daɪˈɡlɒsiə/; from Koine Greek διγλωσσία from δι- prefix "two" (from δίς, "twice"), γλῶσσα, "language" and -ία, suffix denoting state or attribute, "speaking two languages") refers to a situation in which two dialects or languages are used by a single language community. In addition to the community's everyday or vernacular language variety (labelled "L" or "low" variety), a second, highly codified variety (labelled "H" or "high") is used in certain situations such as literature, formal education, or other specific settings, but not used for ordinary conversation.