There are six basic parts of speech, or categories of words with specific functions: noun/pronoun, verb, adverb, adjective, preposition/interjection and conjunction.
Nouns identify a person, place or thing. Horse, Abraham Lincoln and Miami are nouns. Pronouns, such as he, she, or they, take the place or nouns.
Verbs communicate action, events or state of being. Verb tense expresses time. Rode, ride, will ride and would ride are the same verb in various tenses.
Adverbs tell us more about a verb, adjective or another adverb. They answer questions about how, when, where or how much. Adverbs frequently end in -ly, such as slowly or colorfully.
Adjectives modify nouns, almost always appearing before them. Green, rabid and jewel-studded are examples of adjectives.
Prepositions and conjunctions are linking words. Conjunctions (e.g., "and," "when" and "or") link words or phrases. Prepositions connect nouns and pronouns with other parts of the sentence. "On," "for" and "at" are common prepositions, which often begin prepositional phrases, such as "on the road."
Interjections convey emotion. Examples, generally set apart by an exclamation point, include: "oh!," "wow!" and "oh my!" Interjections should be used judiciously.