Pronouns are words that replace nouns in a sentence to avoid repetition and make communication smoother. Common examples include he, she, it, they, and we. Pronouns can refer to people, animals, or objects, helping to clarify who or what is being discussed without constantly repeating names. There are different types of pronouns, such as personal pronouns, which refer to specific people or things, and possessive pronouns, which indicate ownership, like his, her, and their. Understanding pronouns is essential for effective communication, as they help convey meaning and maintain the flow of conversation.