Preamble: Sociolinguistics is the mirror of society. It is not presupposed. We have to mention some important feature and information to justify the comment. To prove this we should clarify some initial terms before discussing further.

Sociolinguistics:
Sociolinguistics is the study of the effect of any and all aspects of society, including cultural norms, expectations, and context, on the way language is used, and the effects of language use on society. Sociolinguistics differs from sociology of language in that the focus of sociolinguistics is the effect of the society on the language, while the latter's focus is on the language's effect on the society.

Sociolinguistics overlaps to a considerable degree with pragmatics. It is
Toward this end, linguistic data are limited to sentences (as the biggest linguistic units) taken from standard language. Generative Grammar is a perfect example of theoretical linguistics. By contrast, in the study of language in its sociocultural context, best represented by Sociolinguistics and Ethno linguistics, variation is the norm.

As noted in passing, linguistic variation is better known as linguistic relativity. In the latest development of the discipline, there has been a pull-and-push tension between relativity and universality in the study of human language. In terms of degree, setting the chronological order aside, linguistic relativity is partly visible in Saussurean structuralism, quite visible in the Bloomfieldian school, highly idealized in the Humboldtian framework, strongly dominating in the Boasian tradition, and well established in the Sapir-Whorf Hypothesis. In our opinion, linguistic relativity is best captured by the neo-Bloomfieldian postulate:
Every language is unique, structurally and culturally.

Going back to the study of language in its sociocultural context, we believe that the most fruitful discussion of linguistic relativity should be related to linguistic universality. The notion of universality is very popular in the Chosmkyan school, but less popular in the Greenbergian school. The former, formulated in the theory of Universal Grammar, is essentially universality