Linguistic prescription, also called prescriptivism or prescriptive grammar, is the establishment of rules defining preferred usage of language. These rules may address such linguistic aspects as spelling, pronunciation, vocabulary, morphology, syntax, and semantics. Sometimes informed by linguistic purism, such normative practices often suggest that some usages are incorrect, inconsistent, illogical, lack communicative effect, or are of low aesthetic value, even in cases where such usage is more common than the prescribed usage. They may also include judgments on socially proper and politically correct language use.

Spelling is a set of conventions for written language regarding how graphemes should correspond to the sounds of spoken language. Spelling is one of the elements of orthography, and highly standardized spelling is a prescriptive element.