Foreword Conversational AI combines ideas from linguistics, human-computer interaction, artificial intelligence, and machine learning to develop voice and chat assistants for a near-infinite set of use cases. Since 2016 there has been a surge in interest in this field, driven by widespread adoption of mobile chat applications. The coronavirus pandemic accelerated this trend, with almost all one-on-one interactions becoming digital. 2016 was also the year Rasa was first released and we saw the first community contributions come in on GitHub. Open source communities live and die by their users and contributors, and this is doubly true for Rasa,where our global community builds assistants in hundreds of human languages. Xiaoquan Kong and Guan Wang have been leading members of our community f…