The rapid advancements in AI technologies, particularly Large Language Models (LLMs), have blurred the lines between AI-Mediated Communication (AI-MC) and Human-Machine Communication/Human-Artificial Intelligence Communication (HMC/HAIC). This paper introduces novel concepts such as AI-Assisted Communication (AI-AC) and AI-Dominated Communication (AI-DC) within AI-MC and proposes a theoretical framework positioning LLMs as communicators with dual sender-receiver roles. The framework is extended to encompass Generative AI technologies, offering a novel perspective on AI's multifaceted role in human communication processes. By integrating insights from diverse research perspectives, the paper contributes to the advancement of communication theory, highlights ethical considerations, and aims to stimulate further investigations into the transformative impact of AI on human communication.Keywords: AI-Mediated Communication, Human-Machine Communication, Large Language Models, AI-Assisted Communication, AI-Dominated Communication, Generative AI