English grammar
Introduction
English grammar is a set of rules that attempt to describes the structural principles of the English language. While grammar is often conceived of as a set of instructions that explains how to form 'proper' sentences, this is only one sense of the term. In modern linguistics, it is used to refer to a complete system of a language that enables its speakers to understand and produce meaningful utterances. This means that while English teachers might want to instruct students about how to form a plural (e.g. "Add an s to the end of a noun"), linguists would be more concerned with placing such changes in the context of a larger model of grammar which is attentive to how language in general is generated, altered, and comprehended. The technical difficulty of such an undertaking -- particularly with a language such as English which has a relatively high proportion of irregular and inconsistent usage -- has deepened the differences between these two senses of the term.
Linguists usually view examples of both 'good' and 'bad' grammar as intrinsically valid, whether or not they conform to the ostensible 'standard'. This descriptive view is often at odds with everyday uses of the word 'grammar', where it is understood to refer to rules that have to be learned. This association of 'grammar' with 'correctness' is a prescriptivist view.
The traditional model of grammar commonly taught in US elementary and secondary schools uses the model of the parts of speech. Within this model, parts of speech are seen as discrete categories: verb, noun, pronoun, adverb, and so on. Within linguistics, however, a different set of models, based more on the function of words rather than their categorization, is preferred. Particularly with English, the model is useful, as we have so many words capable of functioning as several different 'parts of of speech.' The word fish, for instance, can function as a verb, a noun, or an adjective, depending on its syntactic position in a sentence.
Models of Grammar
There are different models of grammar. The two most common ones are prescriptive grammar and descriptive grammar. Prescriptive grammar attempts to codify the rules of a language, while descriptive grammar describes how people use the language.
Parts of Speech Overview
This section provides definitions for the different parts of speech. Each part is explained in detail in a later section.