Interrogative particles are words used in languages to form questions. They help indicate that a sentence is asking for information rather than making a statement. Common examples include words like "is," "are," or "do" in English, which signal that a question is being posed. In many languages, interrogative particles can be added to the end of a statement to turn it into a question. For instance, in Japanese, the particle "か" is used for this purpose. Understanding how these particles function is essential for effective communication and comprehension in various languages.