DIGLOSSIA. A term in SOCIOLINGUISTICS for the use of two varieties of language for different purposes in the same community. The varieties are called H and L, the first being generally a standard variety used for ‘high’ purposes and the second often a ‘low’ spoken vernacular. In Egypt, classical ARABIC is H and local colloquial Arabic is L. The most important hallmark of diglossia is specialization, H being appropriate in one set of situations, L in another: reading a newspaper aloud in H, but discussing its contents in L. Functions generally reserved for H include sermons, political speeches, university lectures, and news broadcasts, while those reserved for L include everyday conversations, instructions to servants, and folk literature.

The varieties differ not only in grammar, phonology, and vocabulary, but also with respect to function, prestige, literary heritage, acquisition, standardization, and stability. L is typically acquired at home as a mother tongue and continues to be so used throughout life. Its main uses are familial and familiar. H, on the other hand, is learned through schooling and never at home, and is related to institutions outside the home. The separate domains in which H and L are acquired provide them with separate systems of support. Diglossic societies are marked not only by this compartmentalization of varieties, but also by restriction of access, especially to H. Entry to formal institutions such as school and government requires knowledge of H. In England, from medieval times until the 18c, Latin played an H role while English was L. In some English-speaking Caribbean the H role is played by local standard English, the L role by English-based creoles.

The extent to which these functions are compartmentalized can be illustrated by the importance attached by community members to using the right variety in the appropriate context. An outsider who learns to speak L and then uses it in a formal speech risks being ridiculed. Members of a community generally regard H as superior to L in a number of respects; in some cases, H is regarded as the only ‘real’ version of a particular language, to the extent that people claim they do not speak L at all. Sometimes, the alleged superiority is avowed for religious and/or literary reasons: the fact that classical Arabic is the language of the Qur'ān endows it with special significance. There is also a strong tradition of formal grammatical study and standardization associated with H varieties: for example, Latin and ‘school’ English. See CODE-MIXING AND CODE-SWITCHING.