diglosszia

Diglossia is a sociolinguistic situation in which two distinct varieties of the same language, or two closely related languages, are used by a speech community in different social contexts. One variety, the high (H) variety, is prestigious and employed in formal education, official discourse, literature, media, and religious contexts. The other, the low (L) variety, is the everyday spoken language used at home and in informal interactions. The two varieties typically differ in phonology, grammar, and vocabulary, and are not simply informal versus formal styles.

In a stable diglossic system, speakers are typically bilingual across registers. The H variety is learned largely through schooling and literacy, while the L variety is acquired through daily use. Code-switching between H and L is common, and the distribution of functions between the varieties tends to persist across generations. Diglossia is distinct from bilingualism in that the two varieties have specialized social domains and prestige rather than representing interchangeable languages in all situations.

Classic examples are often cited. Arabic diglossia features Modern Standard Arabic as the H variety and regional colloquial dialects as L varieties. In Switzerland, Standard German serves as H and Swiss German as L in everyday conversation. The Hindi–Urdu diglossia is frequently described in parts of the Indian subcontinent, where Hindustani underlies both registers, but formal writing and prestige forms align with different standard varieties. Maltese is also discussed in diglossic terms, with Standard Maltese and contact with English affecting domain use.

Notes include that diglossia is not simply two languages side by side, but two functionally distinct varieties of a language; the concept has been extended to extended or triglossia in more complex sociolinguistic systems.