A grammar is a theory of a language; a set of structural rules that governs the valid composition of words, phrases, and clauses in a language.


1   Study

The study of grammars is grammar, a branch of linguistics.

Grammar is one of the core subjects in the trivium.

The dominant theory is generative grammar.

Grammar consists of:

2   Structure

The main units of grammar are words and sentences.

Grammatical units - 2 types of relations:

A morpheme, a word, a phrase and a sentence are units of different levels of language structure. A unit of a higher level consists of one or more units of a lower level.

3   Properties

A grammar must be finite. A grammar cannot simply be a list of all sequence of morpheme since there are infinitely many.

4   Function

Grammars may be used to define infinite sets in a finite way.

5   Classification

There are two ways to go about writing grammatical rules:

  1. Prescriptive rules, which prescribe how people should speak
  2. Descriptive rules, which describe how people actually speak

6   Grading

In Aspects of the Theory of Syntax (1965), Noam Chomsky introduced a hierarchy of levels of adequacy for evaluating grammars. Chomsky claimed that there are three stages a that a grammar can attain. From least adequate to most adequate:

  1. Observationally adequacy
  2. Descriptive adequacy
  3. Explanatory adequacy

6.1   Observational adequacy

A grammar is observationally adequate if it accounts for data in a corpus.

Such a grammar does not tell us what kind of sentences are unacceptable or ill-formed.

6.2   Descriptive adequacy

A grammar is descriptively adequate if it accounts for both corpora and native speaker intuitions about well-formedness.

6.3   Explanatory adequacy

A grammar is explanatorily adequate if it accounts for corpora, native speaker intuitions, and language acquisition.