In other words, pronouns act like stand-ins for nouns we already mentioned. They prevent our sentences from sounding too repetitive and make communication flow smoother. Pronouns are a key part of English grammar because they let us refer back to things without having to say the whole noun again. There are different kinds of pronouns, like ones that act as the subject or object in a sentence, and each kind has a specific job.
Definition and Role of Pronouns in a Sentence

Pronouns replace nouns to make sentences less cumbersome and more fluid. For example, instead of saying, “Maria went to the store because Maria needed milk,” we use the pronoun “she” to replace the second instance of Maria: “Maria went to the store because she needed milk.” This simplifies the sentence and makes it more engaging and less repetitive.
Explanation of Subject and Object Pronouns

Who is doing what? Subject pronouns tell us. In English, the subject pronouns are “I,” “you,” “he,” “she,” “it,” “we,” and “they.” These pronouns are positioned at the beginning of a clause or sentence, directly preceding the verb.
Object pronouns, conversely, are used as the object of a sentence – the person or thing receiving the action. The object pronouns in English include “me,” “you,” “him,” “her,” “it,” “us,” and “them.” These pronouns typically follow the verb or preposition in a sentence.
Basic Rules for Using “I” as a Subject Pronoun and “Me” as an Object Pronoun

Understanding the roles of “I” and “me” hinges on recognizing their positions within a sentence. “I” is a subject pronoun, which should be used when referring to oneself as the subject acting.
For example:

“I am going to the store.”

“John and I are attending the meeting.”
Conversely, “me” is an object pronoun and should be used when referring to oneself as the object receiving the action. For example:

“The teacher called me.”

“Can you send the report to me?”
A common mistake is using “me” and “I” interchangeably, especially when combined with another subject or object. One can remove the other subject or object from the sentence to determine the correct pronoun. For instance, “John and I went to the store” remains correct when simplified to “I went to the store,” while “John and me went to the store” would be incorrect as “Me went to the store” is grammatically wrong.
Following these basic rules and understanding the distinct roles of subject and object pronouns, one can avoid common mistakes and use “I” and “me” correctly in various contexts.