Full Papers -- Developing and Evaluating a Hackathon Approach to Foster Security Learning.-Augmenting the Human-Robot Communication Channel in Shared Task Environments -- Preliminary Utility Study of a Short Video as a Daily Report in Teleworking -- What do we know about hackathon outcomes and how to support them? - A systematic literature review -- Time-position characterization of conflicts: a case study of collaborative editing -- Image-Based Detection Criteria for Cultural Differences in Translation -- Creating Dialogue Between a Tutee Agent and a Tutor in a Lecture Video Improves Students' Attention -- Effect of Cultural Misunderstanding Warning in MT-Mediated Communication -- Challenges for distance learning and online collaboration in the time of COVID-19: Interviews with science teachers -- Learning music and math, together as one: Towards a collaborative approach for practicing math skills with music -- Work-in-Progress Papers -- Quantifying Collaboration Quality in Face-to-FaceClassroom Settings Using MMLA -- Showing-Displays-Together: A Co-located Web Search Support Exploiting the Terminal Orientation -- Travel Plan Recommendation Based on Review Analysis and Preference Diagnosis -- Parents' Reflection with a Digital Family Calendar: A Case of Using Scrapbook Calendars in Japanese Families -- Four Approaches to Developing Autonomous Facilitator Agent for Online and Face-to-face Public Debate.

This book constitutes the proceedings of the 26th International Conference on Collaboration Technologies and Social Computing, CollabTech 2020. The conference was scheduled to take place in Tartu, Estonia, in September 2020. It was held virtually due to the COVID-19 pandemic. The 10 full and 5 work-in-progress papers presented in this volume were carefully reviewed and selected from 25 submissions.