This article examines the colloquial standard of DariDaricolloquial standard of Dari from AfghanistanAfghanistan, which can be considered the most widespread varietyVariety of spoken PersianSpoken Persian in that country. It is assumed that the question of what makes a spoken linguistic varietyVariety standard as opposed to non-standard is not an easy one to answer. Although there cannot be strict either/or distinctions on this question, tendencies in linguistic behaviour can be identified, which are explored in this paper. It is argued that our familiarity with the colloquial standardColloquial standard becomes a key to our understanding of other regional and social varietiesVariety of spoken Dari PersianDariDari Persian in AfghanistanAfghanistan. The paper describes the emergence of the colloquial standard of DariDaricolloquial standard of Dari in the course of the twentieth century and introduces the main characteristic features in phonology, morphology, and syntaxSyntax. From a sociolinguistic perspective, the paper gives attention to the question in which situations and under which circumstances the colloquial standardColloquial standard is typically used.