Conversational Artificial Intelligence (AI) refers to computer systems designed to communicate with humans using natural language through text or voice. These systems aim to simulate human-like conversations by understanding user intent, processing language context, and generating appropriate responses. With rapid advancements in Natural Language Processing (NLP), Machine Learning (ML), and Deep Learning (DL), Conversational AI has become an essential component of modern digital interaction. This research paper explores the concept, evolution, core technologies, architecture, applications, challenges, ethical considerations, and future scope of Conversational AI. The paper provides a comprehensive understanding suitable for academic and introductory research purposes.