An ELT Glossary : Prescriptive grammar and Descriptive grammar

  • Definition : Prescriptive grammar refers to grammatical rules based on someone’s idea of how the language should be used.

  • Examples : “You should never end a sentence with a preposition”; "You should never split an infinitive"; "You should never use a double negative"; You should never use And or But at the beginning of a sentence.

  • This contrasts with descriptive grammar which looks at real instances of how the language is used, and formulates rules based on those.