Two of the principal parts of speech are nouns and verbs, with noun phrases being part of every sentence you can make in English. Understanding the difference between nouns and verbs sometimes gets complicated by the fact that nouns can become verbs and verbs can stand as nouns, but understanding a few basics should help you keep the two straight.

Nouns

Nouns are things: objects, people, places and ideas. If you can give a name to something, it’s a noun. Sometimes, you can count nouns -- dog/dogs -- and sometimes you can’t count nouns -- bread. Nouns play three different roles in a sentence: acting as the subject -- the thing doing the action; the object -- the thing receiving the actions; or as a possessive -- the thing that owns the object. To find a noun, ask yourself who or what the sentence is about. The answer is the noun.

Verbs

Verbs are the movers and shakers of a sentence. A verb is the part of a sentence that has action. Not all verbs are necessarily active things, like running or jumping; they can also be passive activities, like thinking, seeing or just being. If you ask yourself what the subject -- the noun -- of a sentence is doing, the answer will be a verb.

Nouns as Verbs

English is constantly evolving and changing, and with the advent of new technologies and new ways of doing things, new words enter the vocabulary. Technological nouns like “Google” and “Facebook” have become verbs, such as in the sentences “If you don’t know the meaning of something, Google it” and “If you need to contact me, Facebook me.” In both instances, the action -- Google, standing for search, and Facebook, standing for send a message -- is in the form of a noun. Still, you can tell these words are verbs because they are performing the action.

Verbs as Nouns

English is also full of “nominalizations,” words that began as verbs but have entered the vernacular as nouns. For an example, look no further than the colloquially popular expression “epic fail.” As Henry Hitchings points out in his "New York Times" Opinionator Column “Those Irritating Verbs-as-Nouns,” the sentence “That was an epic fail” really means “They failed to an epic degree,” but common usage has led to “fail” -- a verb -- being an acceptable noun. The sentence “That was an epic fail” has “was” as its verb, and “fail” becomes a noun since it’s not doing any action.