ICME-14 brought together researchers from around the world and TSG 39 included a range of researchers from 13 different countries, drawing on a range of different theoretical perspectives, different methodological approaches and with different focuses. Due to the Covid-19 pandemic, the meeting was held in a hybrid format. Part of the presentations were given online via Zoom, and another part at the location of ICME-14, the University of Shanghai, China in a lecture hall. A total of 20 papers and 7 posters were accepted for presentation in TSG39. The papers were presented in 3 sessions over 3 days. In addition, two sessions were dedicated for one invited lecture each. First, Götz Krummheuer (Kassel, Germany) & Marcus Schütte (Leibniz University Hannover, Germany) presented on "Cooperation, Argumentation and Learning - three basic Concepts referring to everyday Procedures in Teaching-Learning Situations in Mathematics Classes" and second, Beth Herbal-Eisenmann (Michigan State University, USA) & Jenni Ingram (Oxford University, UK) presented on "A political look at math communication". The invited lectures enabled TSG participants to reflect on new broader perspectives regarding mathematics and language and to discuss the insights gained on this topic.