Descriptive linguistics is the work of analyzing and describing how language is actually spoken now (or how it was actually spoken in the past), by any group of people. The descriptive linguistics school of thought is opposed to the earlier prescriptive linguistics school, which was concerned rather with making pronouncements on how people ought to speak a language. Accurate description of real speech is a very difficult problem, and linguists have often been reduced to very inaccurate approximations.

Almost all linguistic theory had its origin in practical problems of descriptive linguistics. Phonetics (and its theoretical developments such as phonemes) deals with how native speakers pronounce languages. Syntax has developed to describe what is going on once phonetics has reduced spoken language to a normalized control level. Lexicography 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 a speaker has internalized something called "linguistic competence ", which gives them the ability to correctly extrapolate from their experience new but correct expressions, and to reject unacceptable expressions.

There are tens of thousands of linguistic descriptions of thousands of languages that were prepared by people without adequate linguistic training. With a few honorable exceptions, all linguistic descriptions done before ca. 1900 are amateur productions.

A linguistic description would currently be considered good if it:

1. described the phonology of the language.
2. described the morphology of words.
3. described the syntax of sentences.
4. described the lexical derivations.
5. included a vocabulary with at least a thousand entries.
6. included a few genuine texts.

There are some bonus topics that might also be included, like an analysis of discourse and historical reconstructions.

Currently the most controversial topics are usually morphology and syntax. English has a very meager morphology and an over-emphasized syntax, but in the study of other languages, morphology has revived as an active field of study.

The purpose of linguistic theory, so far as a practical linguist is concerned, is to make descriptions of morphology and syntax comprehensible. It is easy to see that the same data can often be described in different ways. For a while there was an active desire to find some measure which would allow some one description to be called the best. Today that goal seems to have been given up as chimerical.

Descriptivist linguists:

• Edward Sapir