A standard language (also standard dialect or standardized dialect) is a language variety used by a group of people in their public discourse. Alternatively, varieties become standard by undergoing a process of standardization, during which it is organized for description in grammars and dictionaries and encoded in such reference works. Typically, varieties that become standardized are the local dialects spoken in the centers of commerce and government, where a need arises for a variety that will serve more than local needs.

A standard written language is sometimes termed by the German word Schriftsprache.

The only requirement for a variety to be standard is that it can frequently be used in public places or public discourse. The creation of a prescriptive standard language derives from a desire for national (cultural, political, and social) cohesion with this considered as requiring an agreed-upon, standardized language variety.^{[citation needed]} Standard languages commonly feature:

Arabic comprises many varieties (many mutually unintelligible^{[citation needed]}), that are considered a single language, because the standard Arabic register, Modern Standard Arabic, is generally intelligible to all speakers. It is based upon modified Classical Arabic, the language of the Qur'an, the contemporary refined vernacular of Muhammad’s time, the 7th century CE.

Shana Poplack is a leading proponent of variation theory, the approach to language science pioneered by William Labov. She has extended the methodology and theory of this field into bilingual speech patterns, the prescription-praxis dialectic in the co-evolution of standard and non-standard languages, and the comparative reconstruction of ancestral speech varieties, including African American Vernacular English.

She is a Distinguished University Professor in the linguistics department of the University of Ottawa, where she directs the Sociolinguistics Laboratory and holds the Canada Research Chair in Linguistics. Born in Detroit, Michigan, and raised in New York City, she studied at Queens College and New York University, then lived in Paris for several years, studying with André Martinet at the Sorbonne before moving to the University of Pennsylvania, where she took her PhD (1979) under Labov's supervision.

During three years as a researcher at the Centro de estudios puertorriqueños, City University of New York, her studies of code-switching among Puerto Ricans in New York initiated her characterization of universal patterns of intrasentential language mixing, and demonstrated that fluent code-mixing is a bilingual skill rather than a defect. Over three decades, she made numerous contributions to the understanding of bilingual syntax in social context, many involving typologically contrasting language pairs.