In this talk I will provide an overview of the rapidly growing field of Statistical Learning for adaptive Multimodal Dialogue Systems. I first provide some background on Dialogue Systems, their architecture, and (some of) the current research challenges in the field. I argue for the use of statistical methods for dialogue control, as they lead to more robust and adaptive interaction. I focus on two application examples. First, I introduce a Supervised Learning approach to re-ranking dialogue prompts based on predicted Text-To-Speech quality. Then I introduce a 5-step method to "bootstrap" Reinforcement Learning-based dialogue behaviour. We apply this method to optimise Dialogue Management and Natural Language Generation. We evaluate all the results with real users.