There are thousands of words in the English language, but different words have different functions. The eight parts of speech serve as the building blocks of the English language. Learning their functions can help you form grammatically correct sentences, making you a stronger writer and helping you to get a clear message across. The eight parts of speech are verbs, nouns, adjectives, adverbs, pronouns, prepositions, conjunctions and interjections.

Verbs

Verbs are the action words, implying that the subject of the sentence is doing something. Verbs can come in two types: main verbs and helping verbs. Main verbs can stand on their own and not lose their meaning, while helping verbs cannot act without a main verb. For instance, in "she is writing," "is" is the helping verb and "writing" is the main verb. While other parts of speech do not change in form, most verbs do change in form depending on the context of the sentence. For instance, the word "write" has six forms: to write, write, writes, wrote, writing and written.

Nouns

Nouns can simply be defined as a person ("girl," "boy," "doctor"), place ("hospital," "apartment," "school") or thing ("car," "ears," "pasta"). There are several different types of nouns: proper nouns, which refer to specific entities ("California"); common nouns, which refer to general entitles ("state"); countable nouns, which can occur in single and plural forms ("apple"); uncountable nouns ("clutter"); collective nouns, which refer to a group of something ("class," "family," "jury"); concrete nouns, which can be experienced with one of your senses ("dog," "cinnamon"); and abstract nouns, which are theoretical concepts ("freedom").

Adjectives

An adjective is the part of speech that is used to describe nouns. For example, in the phrase "a shaggy dog," "shaggy" serves to modify "dog." Comparative adjectives are adjectives that are used to describe differences between two things. Words such as "bigger," "stronger" and "louder" are comparative adjectives. Superlative adjectives, on the other hand, denote the best quality: "biggest," "strongest," "loudest."

Adverbs

Adverbs modify or describe verbs. Many adverbs end with -ly, such as "smartly," "admiringly" and "faithfully." In the sentence "John acts immaturely," for example, "immaturely" serves as the adverb that modifies "act." There are five types of adverbs: adverbs of time ("next week"); adverbs of frequency ("sometimes"), adverbs of degree ("much"), adverbs of comment ("unfortunately") and adverbs of manner ("gently").

Pronouns

Pronouns are typically short words that can be used in place of a noun. There are several different types of pronouns: personal pronouns ("me," "you," "he," "she"), demonstrative pronouns ("that," "those," "these"), possessive pronouns ("mine," "hers," "yours"), interrogative pronouns ("what," "which," "who"), reflexive pronouns ("herself," "himself," "yourself") and reciprocal pronouns ("each other," "one another").

Prepositions

A preposition is a word that forms a connection between a noun and pronoun and another part of the sentence. There are dozens of prepositions in the English language, and all generally fall into one of three types. Time prepositions include words such as "after," "until" and "during." Place prepositions indicate location and include the words "around" and "between." Direction prepositions include words such as "under" and "toward."

Conjunctions

Conjunctions join words or parts of a sentence. Coordinating conjunctions include "and," "but," "or" and "yet." Subordinating conjunctions include "although," "unless" and "because."

Interjections

Interjections are short words that typically hold little to no value in a sentence but tend to express feeling. Unlike with other parts of speech, there is only one type of interjections. Words such as "ah," "oh" and "um" are considered interjections.