• Language Understanding (NLU/SLU)
• Language Generation
• Dialogue State Tracking
• Policy Optimization (Supervised/Reinforced)
• Dialogue Evaluation
• Dialogue Data Collection/Datasets
• End-to-End Dialogue Modeling
• Multimodal Dialogue
• Discourse Modeling
• Coreference Resolution
• Dialogue Representation Learning
• Conversational AI Deployment
• User Modeling
• Learning from User Feedback
• Human-in-the-loop Dialogue

Dear Colleagues, Conversational AI has seen great progress in recent years, but many challenges still remain to be solved. The more we try to model human–human interaction, the more we realize that conversational AI is an interdisciplinary subject, involving fields that range from machine learning to psychology and sociology. This special issue aims to bring together NLP researchers and practitioners from different fields, alongside experts in speech and machine learning, to advance the current state-of-the-art, share insights and challenges, and bridge the gap between academic research and real-world product deployment. Topics of interest include: • Language Understanding (NLU/SLU) • Language Generation • Dialogue State Tracking • Policy Optimization (Supervised/Reinforced) • Dialogue Evaluation • Dialogue Data Collection/Datasets • End-to-End Dialogue Modeling • Multimodal Dialogue • Discourse Modeling • Coreference Resolution • Dialogue Representation Learning • Conversational AI Deployment • User Modeling • Learning from User Feedback • Human-in-the-loop Dialogue Dr. Alexandros Papangelis Dr. Elnaz Nouri Dr. Bing Liu Dr. Yun-Nung (Vivian) Chen Guest Editors Manuscript Submission Information Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website. Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Information is an international peer-reviewed open access monthly journal published by MDPI. Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.