Diglossia describes a stable situation in which members of a speech community use two distinct varieties of a language (or two related languages) for different social functions. One variety is typically used in formal, written, religious, legal, or literary contexts; the other is used for everyday conversation, family life, and informal interaction. The contrast is about function and prestige rather than simple bilingualism.

Key characteristics

Classic features of diglossia include:

  • A "high" (H) variety that is standardized, codified, and associated with education, ceremony, religion, or literature.
  • A "low" (L) variety that is used in ordinary speech, often more variable and less standardized.
  • Complementary distribution: speakers shift between H and L varieties depending on setting, purpose, and audience.
  • Transgenerational persistence: the pattern can persist across generations even when the varieties influence each other.

Historical and sociolinguistic background

The concept was developed in the mid-20th century to describe stable patterns in multilingual or multi-variety societies. Diglossic arrangements often arise when a prestigious written or liturgical language remains in use alongside evolving everyday speech, or when different standard forms compete for prestige in the same nation. Over time, social change, education, mass media, and language planning can alter or reduce diglossic patterns.

Examples

Well-known examples illustrate different kinds of diglossia. In some Arab countries a standardized literary form has long been used in writing and formal speech while regional colloquial varieties serve daily needs; see Arabic. Classical or literary forms of Chinese have coexisted historically with spoken regional forms; see Chinese. In other situations, two modern written standards serve distinct roles, such as the Norwegian case where two normative written standards relate to the spoken language; see Norwegian and its written traditions Bokmål and Nynorsk. More generally, diglossia concerns the social use of languages and dialects within communities.

Importance and consequences

Diglossia affects literacy, education, identity, and language policy. Learning a high variety may be essential for schooling and official work, creating pressure on speakers of the low variety to acquire additional competence. At the same time, the low variety often carries community identity and carries innovations that can reshape the high variety over time.

Diglossia is related to but distinct from bilingualism, code-switching, and language shift. Bilingualism refers to competence in two languages; diglossia emphasizes functional separation. Code-switching can occur within diglossic communities as speakers move between H and L varieties. Sociolinguists study these patterns to understand how language, power, and culture interact in everyday life.