diglossic

noun

1. the widespread existence within a society of sharply divergent formal and informal varieties of a language each used in different social contexts or for performing different functions, as the existence of Katharevusa and Demotic in modern Greece.
2. Pathology. the presence of two tongues or of a single tongue divided into two parts by a cleft.

noun

1. linguistics the existence in a language of a high, or socially prestigious, and a low, or everyday, form, as German and Swiss German in Switzerland

n.

1. bifid tongue