In the study of language, description or descriptive linguistics is the work of objectively analyzing and describing how language is actually used (or how it was used in the past) by a speech community.

All academic research in linguistics is descriptive; like all other scientific disciplines, it aims to describe reality, without the bias of preconceived ideas about how it ought to be. Modern descriptive linguistics is based on a structural approach to language, as exemplified in the work of Leonard Bloomfield and others. This type of linguistics utilizes different methods in order to describe a language such as basic data collection, and different types of elicitation methods.

Linguistic description, as used in academic and professional linguistics, is often contrasted with linguistic prescription, which is found especially in general education, language arts instruction, and the publishing industry.

As English-linguist Larry Andrews describes it, descriptive grammar is the linguistic approach which studies what a language is like, as opposed to prescriptive, which declares what a language should be like. In other words, descriptive grammarians focus analysis on how all kinds of people in all sorts of environments, usually in more casual, everyday settings, communicate, whereas prescriptive grammarians focus on the grammatical rules and structures predetermined by linguistic registers and figures of power. Andrews also believes that, although most linguists would be descriptive grammarians, most public school teachers tend to be prescriptive.

Webster's Third New International Dictionary was the subject of controversy over its use of linguistic description. It included words, pronunciations, and meanings that previous dictionaries would omit. It also labeled words such as ain't as "nonstandard," while older, prescriptive dictionaries may use terms such as "improper," "incorrect," or even "illiterate." This descriptive approach, while common in sociolinguistics, was seen as overly permissive by many who felt dictionaries ought to approach language prescriptively.

The earliest known descriptive linguistic work took place in a Sanskrit community in northern India; the most well-known scholar of that linguistic tradition was Pāṇini, whose works are commonly dated to around the 5th century BCE. Philological traditions later arose around the description of Greek, Latin, Chinese, Tamil, Hebrew, and Arabic. The description of modern European languages did not begin before the Renaissance – e.g. Spanish in 1492, French in 1532, English in 1586; the same period saw the first grammatical descriptions of Nahuatl (1547) or Quechua (1560) in the New World, followed by numerous others.

Even though more and more languages were discovered, the full diversity of language was not yet fully recognized. For centuries, language descriptions tended to use grammatical categories that existed for languages considered to be more prestigious, like Latin.

Linguistic description as a discipline really took off at the end of the 19th century, with the Structuralist revolution (from Ferdinand de Saussure to Leonard Bloomfield), and the notion that every language forms a unique symbolic system, different from other languages, worthy of being described “in its own terms”.