Definition:
Diglossia is a stable sociolinguistic situation in a speech community in which two distinct varieties of language coexist, with each assigned to functionally separate domains. The H (High) variety is used in formal, literary, and public contexts and carries social prestige; the L (Low) variety is used in informal, domestic, and everyday speech. Crucially, the H variety is typically not acquired natively — it must be formally learned — while the L variety is the mother tongue.
Ferguson’s Original Definition (1959)
Charles Ferguson coined the term diglossia in a foundational 1959 paper examining four situations:
- Arabic — Modern Standard Arabic (H) vs. regional colloquial varieties (L)
- Swiss German — Standard German (H) vs. Schweizerdeutsch/Swiss German (L)
- Haitian Creole — French (H) vs. Haitian Creole (L)
- Greek — Katharevousa (H) vs. Demotiki (L)
Ferguson identified nine criteria distinguishing H from L: function, prestige, literary heritage, acquisition, standardization, stability, grammar, lexicon, and phonology.
Fishman’s Extension
Joshua Fishman later broadened the concept to include bilingual diglossia — situations where an entirely different language fills the H role (e.g., Latin in medieval Europe, English in postcolonial nations, Spanish for indigenous communities). This extended diglossia to cover most multilingual societies.
The H/L Distinction in Detail
| Dimension | H variety | L variety |
|---|---|---|
| Acquisition | Formal education | First language (at home) |
| Prestige | High (“correct language”) | Low (“informal,” “vulgar”) |
| Written use | Dominant | Rare to absent |
| Literary heritage | Extensive | Limited or oral only |
| Religion | Often used | Often not used |
| Political speech | Yes | No |
| Domestic talk | No | Yes |
| Friends’ conversation | No | Yes |
Stability of Diglossia
Ferguson emphasized that diglossia can be remarkably stable over centuries. Arabic diglossia has persisted for 1,400+ years. Swiss German diglossia remains stable today despite Germany’s political dominance of Standard German. The H variety doesn’t displace the L; each occupies its domain.
Diglossia vs. Bilingualism
These can coincide or not:
- Diglossia + bilingualism: Two languages used, with H/L distinction (English + Spanish in bilingual US communities where Spanish is informal and English is formal)
- Diglossia without bilingualism: Only one language community, but H/L varieties are functionally distinct (classical Arabic situation)
- Bilingualism without diglossia: Both languages used in all domains without functional differentiation
- Neither: Monolingual, monodialectal community (rare)
Modern Arabic as a Living Example
Modern Standard Arabic (MSA / Fusha فصحى) is the H variety:
- Used in news broadcasts, formal speeches, official documents, literature
- Learned in school; no child acquires it as a first language
- No native speaker speaks it in casual conversation
Egyptian Arabic, Syrian Arabic, Moroccan Darija, Gulf Arabic, etc. are L varieties:
- Learned at home as mother tongues
- Mutually partially unintelligible across regions
- Barely written; rarely used in formal contexts
This creates a paradox for language learners: learning MSA makes you literate but unable to converse naturally; learning a colloquial makes you conversational but unable to read classical texts.
SLA Connection
- L2 learners of Arabic, Greek (historically), or other diglossic languages must decide which variety to target and why
- Diglossia creates bidialectal demands: native speakers must maintain two systems, and learners must choose an entry point
- The H variety as a “prestige form” connects to prestige language and standard language ideology
History
The term diglossia was introduced to linguistics by Charles Ferguson in 1959 in a landmark Word journal article examining Arabic, Swiss German, Haitian Creole, and Modern Greek — all communities in which a prestigious H (High) variety coexisted with a vernacular L (Low) variety in complementary functional distribution. Ferguson’s original definition required the two varieties to be genetically related (varieties of the same language). Joshua Fishman (1967) extended the concept to include situations of bilingualism, where two genetically unrelated languages occupy H and L functions in a community — what became known as extended diglossia. Subsequent work in sociolinguistics and linguistic anthropology further refined diglossia to address the fluid, contested, and ideologically loaded nature of H/L distinctions in real communities, moving away from Ferguson’s more static structural description.
Common Misconceptions
“All bilingual communities are diglossic.” Diglossia requires a specific functional distribution of varieties — H for formal, public, written domains and L for informal, private, spoken domains. Many bilingual communities use their two languages in patterns that do not fit this complementary functional distribution. Some communities show domain overlap, bidirectional prestige, or code-switching that defies clear H/L assignment.
“The H variety is always the more prestigious one for all speakers.” While the H variety typically carries official prestige and institutional support, community members may hold strong positive attitudes toward the L variety as an authentic marker of in-group identity. Prestige is ideologically constructed and contested — L varieties can carry covert prestige and function as powerful identity signals even in communities that officially valorize the H variety.
Criticisms
Ferguson’s original formulation of diglossia has been criticized for its descriptive essentialism — presenting a static snapshot of H/L distribution that does not capture the dynamic, contested, and historically changing nature of real diglossic situations. The concept was criticized for treating communities as linguistically homogeneous and for underemphasizing power, colonialism, and deliberate language planning in shaping H/L distributions. Sociolinguists working in Arabic diglossic communities have documented continua of variation between High and Low that contradict the sharp functional distinction Ferguson described. The extension of the concept by Fishman to bilingualism-with-diglossia situations stretched the term so broadly that some researchers questioned its analytical precision.
Social Media Sentiment
Diglossia is discussed in linguistics education content and in communities of speakers of diglossic languages. Arabic learners frequently encounter diglossia as the explanation for why Modern Standard Arabic (MSA) differs sharply from spoken dialects — a practical learning challenge that this theoretical concept illuminates. Japanese learners discuss the formal/informal register spectrum (though Japanese is not classically diglossic) in terms conceptually adjacent to diglossia. Greek speakers and learners discuss the historical diglossia between Katharevousa and Demotic Greek as context for understanding modern Greek language history.
Last updated: 2026-04
Practical Application
Diglossia is directly relevant for learners of languages where a formal/written variety differs significantly from spoken vernaculars. Arabic learners face classical language learning diglossia: they must navigate the relationship between Modern Standard Arabic (used in formal and written contexts) and regional colloquials (used in everyday speech). Understanding diglossia helps learners make conscious decisions about which variety to prioritize for their specific communicative goals, rather than assuming a single unified “target language.”
Related Terms
See Also
Research
Ferguson, C. A. (1959). Diglossia. Word, 15(2), 325-340.
The foundational paper introducing the term diglossia to describe communities in which two functionally differentiated varieties of a language coexist — the starting point for all subsequent theoretical and empirical work on this sociolinguistic phenomenon.
Fishman, J. A. (1967). Bilingualism with and without diglossia; diglossia with and without bilingualism. Journal of Social Issues, 23(2), 29-38.
Extends Ferguson’s concept to encompass bilingual communities where two genetically unrelated languages occupy diglossic functional roles, broadening the framework to address the full range of societal bilingualism-diglossia combinations.
Hudson, A. (2002). Outline of a theory of diglossia. International Journal of the Sociology of Language, 157, 1-48.
A theoretical consolidation of diglossia research addressing the definitional debates, the extensions of Ferguson’s original concept, and a framework for analyzing diglossia in contemporary multilingual settings — the most thorough modern review of the concept’s theoretical status.