In the rapidly evolving landscape of speech and language technologies (SLT), the integration of reinforcement learning (RL) has emerged as a powerful paradigm for addressing the challenges of uncertainty and creating adaptive, personalized, and robust systems. This chapter explores the importance of RL+SLT in the context of today’s technological advancements and societal needs. We delve into the key factors driving the growth of RL+SLT, including the rise of large language models (LLMs), the demand for more natural and context-aware human-machine interactions, and the potential for transforming various domains such as education and healthcare. Through concrete examples and discussions, we illustrate how RL+SLT is poised to revolutionize the way we develop and deploy speech and language systems, unlocking new possibilities for human-machine collaboration and interaction. As we navigate the challenges and opportunities ahead, this chapter serves as a roadmap for understanding the significance of RL+SLT and its role in shaping the future of AI.