Why is a standard language also considered a dialect by linguists?

In linguistics, a standard language is considered a dialect because it is essentially a variety of a language that has been elevated through social, political, or historical processes. While the term "dialect" is often incorrectly used to denote substandard speech that deviates from an accepted norm, linguists define a dialect technically as any form of a language peculiar to a community of speakers.12

A standard language functions as a dialect that has attracted special prestige. It typically originates from a specific regional dialect—often that of a capital city or a major cultural and economic center—which is then standardized through written forms, grammars, and dictionaries. Because it shares the same fundamental linguistic structure as other dialects of the same language, it is categorized as one of them.13

Ultimately, a language is viewed by linguists as the sum of its dialects or a generalization based on them. The distinction between a "standard" and other dialects is therefore not a difference in linguistic nature, but rather a result of the social status and institutional support granted to that specific variety.231