Parts of Speech

Words in a sentence can be divided into different parts of speech. Although English may be categorized into more than eight parts of speech, words in a sentence can be classified traditionally into eight parts of speech only for sake of simplicity. They are noun, pronoun, adjective, verb, adverb, preposition, conjunction, and interjection. However, a word itself can be more than one part of speech.

The function of each part of speech can be summarized as following:

Part of Speech	Description
Noun	to represent a thing directly.
Pronoun	to represent a thing indirectly.
Adjective	to add something to the meaning of the thing, e.g. noun, pronoun.
Verb	to express a matter of doing something about something, e.g. noun, pronoun.
Adverb	to add something to the meaning of something, e.g. adjective, verb, adverb.
Preposition	to add a relation between something and a thing
Conjunction	to add a relation between words of expressions.
Interjection	to express some sudden feeling in addition to an expression.

The relationship of each part of speech may be represented by the following figure.

Besides the eight parts of speech, words "a", "an", and "the" in traditional English are called articles which are usually considered as a special type of adjective. But sometimes articles are combined with other demonstratives to form another part of speech called determiner.