In the study of language, description, or descriptive linguistics, is the work of objectively analyzing and describing how language is spoken (or how it was spoken in the past) by a group of people in a speech community. All scholarly research in linguistics is descriptive; like all other sciences, its aim is to observe the linguistic world as it is, 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. Linguistic description is often contrasted with linguistic prescription, which is found especially in education and in publishing. Prescription seeks to define standard language forms and give advice on effective language use, and can be thought of as a presentation of the fruits of descriptive research in a learnable form, though it also draws on more subjective aspects of language aesthetics. Prescription and description are complementary, but have different priorities and sometimes are seen to be in conflict. Descriptivism is the belief that description is more significant or important to teach, study, and practice than prescription.
As English-linguist Larry Andrews describes it, descriptive grammar is the linguistic approach that studies what a language is like, as opposed to prescriptive grammar, which declares what a language should be like.  In other words, descriptive grammarians focus analysis on how all sorts of people in all sorts of environments, usually in more casual, everyday settings, communicate, while prescriptive grammarians focus on the grammatical rules and structures predetermined by linguistic registers and figures of power for those who are under the control of said authorities to use. An example Andrews uses in his book is fewer than vs less than.  A descriptive grammarian would state that, both statements are correct, as long as the receiver of the message can understand the meaning behind the statement. A prescriptive grammarian, on the other hand, would analyze the rules and conventions behind the statements made and determine which statement is correct according to those rules.
Accurate description of real speech is a difficult problem, and linguists have often been reduced to approximations. Almost all linguistic theory has its origin in practical problems of descriptive linguistics. Phonology (and its theoretical developments, such as the phoneme) deals with the function and interpretation of sound in language. Syntax has developed to describe the rules concerning how words relate to each other in order to form sentences. Lexicology collects "words" and their derivations and transformations: it has not given rise to much generalized theory.
An extreme "mentalist" viewpoint denies that the linguistic description of a language can be done by anyone but a competent speaker. Such speakers have internalized something called "linguistic competence", which gives them the ability to extrapolate correctly from their experience new but correct expressions, and to reject unacceptable expressions.
A linguistic description is considered descriptively adequate if it achieves one or more of the following goals of descriptive linguistics:
- A description of the phonology of the language in question.
- A description of the morphology of words belonging to that language.
- A description of the syntax of well-formed sentences of that language.
- A description of lexical derivation.
- A documentation of the vocabulary, including at least one thousand entries.
- A reproduction of a few genuine texts.
- Sapir-Whorf hypothesis
- GOLD (ontology)
- Ludwig Wittgenstein
- Grammatical gender
- Text linguistics
- Kordić, Snježana (2010). Jezik i nacionalizam [Language and Nationalism]. Rotulus Universitas (in Serbo-Croatian). Zagreb: Durieux. p. 60. ISBN 978-953-188-311-5. LCCN 2011520778. OCLC 729837512. OL 15270636W. Archived from the original on 8 July 2012. Retrieved 11 August 2012.
- Andrews, Larry (2006). Language Exploration and Awareness: A Resource Book for Teachers. Mahwah, NJ: Lawrence Earlbaum Associates, Inc., Publishers. p. 25. ISBN 0-8058-4308-6.
- Andrews, Larry (2006). Language Exploration and Awareness: A Resource Book for Teachers. Mahwah, NJ: Lawrence Earlbaum Associates, Inc., Publishers. p. 26. ISBN 0-8058-4308-6.
- Antoinette Renouf, Andrew Kehoe, The Changing Face of Corpus Linguistics – 2006 – 408 pages, p. 377
- Patrick R. Bennett, Comparative Semitic Linguistics: A Manual – 1998 – 269 pages, p. 3
- William A. Haviland, PRINS, WALRATH, Harald E. L. Prins, Dana Walrath, Bunny McBride, Cultural Anthropology: The Human Challenge – HAVILAND – 2004 – 496 pages, p. 93