prescriptive

Etymology

From Latin praescriptivus (“relating to a legal exception”), from praescript- (“directed in writing”), from the verb praescribere.

adj

1. Of or pertaining to prescribing or enjoining, especially an action or behavior based on a norm or standard.
   For one thing, spoken language tends to be less subjected to prescriptive pressures than written language, and hence is a less artificial medium of com- munication (written language is often a kind of 'censored' version of spoken language). … 1988, Andrew Radford, Transformational Grammar, Cambridge: University Press, page 8