There are eight different parts of speech in the English language: verbs, nouns, adjectives, adverbs, prepositions, conjunctions, interjections and articles. The parts of speech describe the function of a word, not its meaning. One word can have different functions. The function depends on how a word is used in a sentence. For example: the word fast can be an adverb or an adjective. In the sentence The dog runs fast., fast is an adverb. In the sentence It's a fast dog., fast is an adjective. Learn more by using our extensive study material on the eight parts of speech.