All words in the English language fall into one of several major categories, called "parts of speech." The parts of speech in English are the noun, verb, adjective, adverb, pronoun, preposition, determiner, conjunction and interjection. Parts of speech can be distinguished based on their function in the sentence, their relationship with other words in the sentence and, to a certain extent, their meaning.
Pronouns are often considered to be a subclass of nouns because they often fulfill the same roles in the sentence. That is why it is easy to confuse them.
The main difference between nouns and pronouns is that nouns name a person, thing or idea and don't require an antecedent, while pronouns replace nouns and require an antecedent in the previous sentence.
What Is a Noun?
A noun is said to be a word that identifies a person or animal (girl, postman, human, grandma, horse), a thing (flower, pot, ceiling, jam, hat, grass) or an idea or state (freedom, anxiety, democracy, blindness, joy). A better way to identify a noun from other parts of speech is by its morphological features (suffixes and prefixes) and their position and function in a sentence.
There are specific features that help you distinguish a noun from other parts of speech. Nouns are often preceded by a determiner like "the," "a" or "an." There are common nouns and proper nouns. Proper nouns are names and begin with a capital letter. Nouns can be singular or plural (apple vs. apples) and can show possession (Jenny’s apple).
A good way distinguish a noun from other parts of speech is to look at its function in a sentence. Some of the common roles of a noun are a subject, direct object, indirect object and an object of a preposition, for example:
Jenny likes jam – “Jenny” is the subject and “jam” is the direct object.
Jenny gave Margaret some jam – “Margaret” is the indirect object.
Jenny enjoys eating jam with friends – “friends” is the object of a preposition.
Noun vs. Pronoun
Pronouns are actually a subclass of nouns because they often replace a noun and can complete the same function in a sentence. For example:
Jenny will arrive tomorrow. She will bring some jam.
The subjects of the first and second sentences refer to the same individual: Jenny. However, instead of repeating the noun “Jenny,” a pronoun is used in the second sentence. Without pronouns, we would have to repeat the same noun over and over, which would make the language sound quite awkward.
Unlike nouns, pronouns need an antecedent – that is, something or someone mentioned in a previous sentence to which they refer. For instance, if you were to start a conversation with the sentence "He is so irresponsible," we wouldn’t know to whom you are referring. However, if you instead said "James ate all the jam. He is so irresponsible," then things would be more clear. “James” here is the antecedent of “he.”
What Are Personal Pronouns?
Personal pronouns refer to one of three different “persons." First-person pronouns refer to the speaker (I or we). Second-person pronouns refer to the addressee (you). Third-person pronouns refer to the person or thing being spoken about (he, she, it, they).
Like nouns, personal pronouns can be either subjects or objects of a sentence. However, unlike nouns, they actually take different forms depending on the position in which they appear. If they are the subject of the sentence, they take nominative case, and if they’re an object, they appear in objective case. In the case of third-person pronouns, they also have to agree in gender (feminine or masculine) with their antecedent. For example, in the sentence "She likes jam," the word "she" is a third-person pronoun that appears in a nominative case because it is a subject of the sentence. However, in the sentence "John likes her," the third-person pronoun appears as an object, so it takes objective case. Nominative and objective forms look like the following for all personal pronouns:
First-person singular pronouns: nominative "I," objective "me"
First-person plural pronouns: nominative "we," objective "us"
Second-person singular and plural pronouns: nominative "you," objective "you"
Third-person singular pronouns: nominative "he, she, it," objective "him, her, it"
Third-person plural pronouns: nominative "they," objective "them"